Canonical Ubuntu Linux Linux Operating System

util-linux 2.41.3: parse_dos_extended int overflow bypass (false partition)
CVE-2026-53615 8 - High - October 14, 2026

util-linux is a random collection of Linux utilities. Before util-linux 2.41.4, `parse_dos_extended()` in `libblkid/src/partitions/dos.c` computes an extended-partition start sector with 32-bit addition and does not apply the extended-area bounds checks to the first two EBR entries. A local attacker who causes a crafted DOS extended-partition disk image or removable medium to be probed can wrap `cur_start + start` to sector zero and cause libblkid to report a false partition overlapping the MBR. This directly compromises the integrity of the reported partition metadata; disk modification or availability loss requires a separate downstream consumer to act on that metadata. This issue is fixed in 2.41.4.

Integer Overflow or Wraparound

util-linux mount SUID race: unprotected bind-mount (2.39.12.41.4/2.42.1)
CVE-2026-53614 7 - High - October 14, 2026

util-linux is a random collection of Linux utilities. In util-linux 2.39.1 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility reads the attacker-controlled `LIBMOUNT_FORCE_MOUNT2` environment variable with `getenv()`, allowing a local low-privileged user to force the non-atomic legacy bind-mount path. With an `/etc/fstab` bind mount authorized by `user` or `users` and protected by `nosuid`, `noexec`, or `nodev`, an attacker can race the window between the initial bind mount and the remount that applies those security flags and execute a SUID program from the temporarily unprotected mount, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2.

Improper Privilege Management

Root Priv Esc via fstab 'user' Mount in util-linux 2.172.42.4
CVE-2026-53613 7 - High - October 14, 2026

util-linux is a random collection of Linux utilities. In util-linux 2.17 through 2.41.6 and 2.42 through 2.42.3, and in 2.42.4 when the legacy `mount(2)` path is used without `/proc`, restricted non-root `mount` requests validate an `/etc/fstab` target before the mount operation re-resolves that pathname. A local low-privileged user authorized by an fstab `user` or `users` entry whose target has an attacker-writable ancestor can use `renameat2(RENAME_EXCHANGE)` to swap a path component and redirect an authorized mount to a root-owned location, such as mounting attacker-controlled content over `/etc/sudoers.d`, and thereby gain root privileges. Versions 2.41.5 and 2.42.2 pin targets for the new mount API, and 2.42.4 pins legacy targets through `/proc/self/fd`; the documented legacy fallback without `/proc` remains affected.

TOCTTOU

util-linux SUID mount escalation via renameat2 race (2.39-2.41.4, 2.42-2.42.1)
CVE-2026-53612 7 - High - October 14, 2026

util-linux is a random collection of Linux utilities. In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility's `hook_owner.c` post-mount hook performs path-based `chmod()` and `lchown()` operations on a previously validated mount target. A local low-privileged user authorized by an `/etc/fstab` entry with `user` or `users` and an `X-mount.mode`, `X-mount.owner`, or `X-mount.group` option can use `renameat2(RENAME_EXCHANGE)` to race a writable ancestor of the target and redirect the privileged ownership or mode change to a root-owned path, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2.

TOCTTOU

OpenVPN 2.6.0-2.6.22 UAF in TLS Session Promotion (CVE-2026-84471)
CVE-2026-84471 7.2 - High - October 14, 2026

The fix for CVE-2026-12996 was incomplete. A use-after-free in OpenVPN 2.6.0 through 2.6.22 and 2.7_alpha1 through 2.7.7 allows remote authenticated peers to potentially cause a denial of service or leak memory via crafted packets during TLS session promotion or expiry.

Dangling pointer

Curl HTTP/2 RST_STREAM UAF during upload
CVE-2026-92392 8.1 - High - October 14, 2026

During an upload, curl mishandles HTTP/2 `RST_STREAM` received from the server (with reason `HTTP_1_1_REQUIRED` or `REFUSED_STREAM`) leading to a use after free of a `struct Curl_easy` object.

Dangling pointer

NTFS-3G <2026.7.7: OOB Read in ntfs_fix_file_name() via readlink
CVE-2026-46571 5.5 - Medium - October 07, 2026

In NTFS-3G before 2026.7.7, a out-of-bounds read exists in ntfs_fix_file_name() in libntfs-3g/reparse.c that allows an attacker to read possibly confidential information in ntfs-3g process memory by crafting a malicious NTFS image. The out-of-bounds read is triggered by a readlink on a corrupted file.

Out-of-bounds Read

NTFS-3G <2026.7.7 heap BOF in ntfs_ib_cut_tail() libntfs-3g/index.c
CVE-2026-46572 7.4 - High - October 07, 2026

In NTFS-3G before 2026.7.7, a heap buffer overflow exists in ntfs_ib_cut_tail() in libntfs-3g/index.c that allows an attacker to corrupt heap memory in the SUID-root ntfs-3g binary by crafting a malicious NTFS image. The overflow is triggered by creating a file in a specially crafted directory.

Heap-based Buffer Overflow

Heap Overflow in ntfs-3g before 2026.7.7 (ntfs_index_walk_down) via SUID root
CVE-2026-46570 8.1 - High - October 07, 2026

In NTFS-3G before 2026.7.7, a heap buffer overflow exists in ntfs_index_walk_down() in libntfs-3g/index.c that allows an attacker to corrupt heap memory in the SUID-root ntfs-3g binary by crafting a malicious NTFS image. The overflow is triggered by reading the special crafted file metadata.

Heap-based Buffer Overflow

NTFS-3G <2026.7.7 Heap Buffer Overflow in ntfs_ib_copy_tail()
CVE-2026-46569 7.7 - High - October 07, 2026

In NTFS-3G before 2026.7.7, a heap buffer overflow exists in ntfs_ib_copy_tail(), in libntfs-3g/index.c, that allows an attacker to corrupt heap memory in the SUID-root ntfs-3g binary by crafting a malicious NTFS image. The overflow is triggered by extending a directory, e.g., by creating a file.

Heap-based Buffer Overflow

NTFS-3G <=2026.7.7 Heap Buffer Overflow in ntfscat
CVE-2026-42616 - October 07, 2026

In NTFS-3G before 2026.7.7, a heap buffer overflow exists in cat() in ntfscat.c that allows an attacker to corrupt heap memory in the ntfscat binary by crafting a malicious NTFS image. The overflow is triggered by reading a file.

NTFS-3G <2026.7.7 heap ble in ntfs_ir_to_ib() SUID binary
CVE-2026-42617 7.1 - High - October 07, 2026

In NTFS-3G before 2026.7.7, a heap buffer overflow exists in ntfs_ir_to_ib() in index.c that allows an attacker to corrupt heap memory in the SUID-root ntfs-3g binary by crafting a malicious NTFS image. The overflow is triggered by extending a directory, e.g., by creating a file.

Heap-based Buffer Overflow

NTFS-3G<2026.7.7 Heap Buffer Overflow in ntfs_decompress()
CVE-2026-42618 7.1 - High - October 07, 2026

In NTFS-3G before 2026.7.7, a heap buffer overflow exists in ntfs_decompress() in compress.c that allows an attacker to corrupt one byte of heap memory in the SUID-root ntfs-3g binary by crafting a malicious NTFS image. The overflow is triggered by reading the special crafted file.

Heap-based Buffer Overflow

YAML Perl Module <1.27_001: glob injection allows arbitrary code exec
CVE-2019-25777 7.3 - High - October 05, 2026

YAML versions before 1.27_001 for Perl allow a loaded perl/glob document to replace any package variable, which can lead to arbitrary code execution. A perl/glob document names a package and a symbol, and supplies the value assigned to it. Nothing restricts the name, so the target can be @INC or YAML's own load options. A perl/glob document that sets $YAML::LoadCode or $YAML::UseCode turns on code loading, which is off by default, for every later Load() in the process. A perl/code document is then passed to a string eval, so an attacker who supplies two documents to separate Load() calls in one process can execute arbitrary Perl code.

Improper Control of Dynamically-Identified Variables

YAML <1.30 (Perl) DESTROY RCE via yaml_loader
CVE-2017-20285 9.1 - Critical - October 05, 2026

YAML versions before 1.30 for Perl allow a loaded document to trigger the DESTROY method of arbitrary classes. A perl/hash:Class tag blesses a hash into the class it names. The document supplies the object's fields, and Perl calls DESTROY when it goes out of scope. What DESTROY does depends on the classes the process has loaded. With File::Temp::Dir from core Perl, it can delete a directory tree the document names.

Marshaling, Unmarshaling

Apache HTTP Server: NULL pointer deref in mod_xml2enc before 2.4.69
CVE-2026-63686 7.5 - High - October 01, 2026

A NULL pointer dereference in mod_xml2enc in Apache Software Foundation Apache HTTP Server before 2.4.69 on all platforms allows an untrusted backend server to cause a denial of service via a proxied response with a charset whose conversion partially succeeds then fails. Users are recommended to upgrade to version 2.4.69, which fixes this issue.

NULL Pointer Dereference

Apache HTTP Server 2.4.68 mod_dav_fs Integer Overflow via PROPPATCH
CVE-2026-93546 8.8 - High - October 01, 2026

Integer overflow in mod_dav_fs in Apache HTTP Server through 2.4.68 allows an authenticated WebDAV client with write access to crash worker processes and persistently corrupt a directory's property database via PROPPATCH requests declaring many XML namespaces.

Integer Overflow or Wraparound

Apache HTTP Server 2.4.x Path Equivalence in mod_userdir (UserDir)
CVE-2026-79768 5.3 - Medium - October 01, 2026

Path equivalence: '/./' (single dot directory) vulnerability in Apache HTTP Server's mod_userdir module when configured with absolute non-wildcard UserDir directive (the 2nd form in https://httpd.apache.org/docs/2.4/mod/mod_userdir.html#userdir) This issue affects Apache HTTP Server: from 2.4.0 through 2.4.68.

Single Dot Directory

UAF in Apache HTTP Server 2.4 mod_auth_digest before 2.4.69
CVE-2026-73637 7.3 - High - October 01, 2026

Use after free in mod_auth_digest in Apache Software Foundation Apache HTTP Server before 2.4.69 on all platforms allows an unauthenticated remote client to cause authentication state corruption via concurrent Digest authentication requests when AuthDigestNcCheck is enabled or AuthDigestNonceLifetime is set to 0. Users are recommended to upgrade to version 2.4.69, which fixes this issue.

Dangling pointer

Apache HTTP Server 2.4.x AuthDigestNonceLifetime 0 Bypass via Capture-Replay MITM
CVE-2026-73636 8.1 - High - October 01, 2026

Authentication bypass by capture-replay in mod_auth_digest in Apache Software Foundation Apache HTTP Server 2.4.x on all platforms allows a man-in-the-middle (MITM) attacker to replay captured digest authentication credentials via crafted requests that trigger garbage collection of the client's shared memory entry when AuthDigestNonceLifetime is set to 0. Users are recommended to upgrade to version 2.4.69, which fixes this issue.

Authentication Bypass by Capture-replay

Apache HTTP Server 2.4.30-2.4.68 Response Smuggling via mod_proxy_uwsgi
CVE-2026-63718 7.5 - High - October 01, 2026

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') response smuggling vulnerability in Apache HTTP Server via mod_proxy_uwsgi and a crafted uwsgi response with Transfer-Encoding. This issue affects Apache HTTP Server: from 2.4.30 through 2.4.68.

HTTP Request Smuggling

Apache HTTP 2.4.68 Buffer Overflow via Host Header > 8192 in mod_vhost_alias
CVE-2026-63292 7.5 - High - October 01, 2026

Stack-based buffer overflow in mod_vhost_alias in Apache Software Foundation Apache HTTP Server through 2.4.68 on all platforms allows a remote client to cause a denial of service or potentially execute arbitrary code via an HTTP request with a Host header exceeding 8192 bytes when VirtualDocumentRoot uses a hostname format specifier and LimitRequestFieldSize is raised above the default. Users are recommended to upgrade to version 2.4.69, which fixes this issue.

Stack Overflow

Improper FTP PASV Validation in mod_proxy_ftp (Apache HTTP Server) <2.4.69
CVE-2026-63045 7.5 - High - October 01, 2026

Improper validation of FTP PASV reply address in mod_proxy_ftp in Apache Software Foundation Apache HTTP Server through 2.4.68 on all platforms allows, in forward proxy configurations, an untrusted FTP server to cause the proxy to open a data connection to an arbitrary third-party host via a crafted PASV response. Users are recommended to upgrade to version 2.4.69, which fixes this issue.

Authorization

Apache HTTP Server 2.4.0-2.4.68 mod_dav_fs State File Disclosure
CVE-2026-58415 5.3 - Medium - October 01, 2026

Internal state files accessible to external parties in mod_dav_fs in Apache Software Foundation Apache HTTP Server before 2.4.69 on all platforms allows a remote client to read WebDAV dead properties of resources it cannot author via a GET request for the .DAV state directory This issue affects Apache HTTP Server: from 2.4.0 through 2.4.68.

Files or Directories Accessible to External Parties

U-Boot <2026.10-rc5 OOB read in dhcp6_parse_options via DHCPv6
CVE-2026-74225 7.1 - High - September 29, 2026

U-Boot before 2026.10-rc5 contains out-of-bounds memory access in dhcp6_parse_options() that fails to validate SERVERID and CLIENTID option lengths from DHCPv6 packets. Attackers on the local network can send crafted DHCPv6 ADVERTISE or REPLY packets during netboot to corrupt memory and crash the bootloader.

Memory Corruption

U-Boot <2026.10-rc5 Use-After-Free in httpc_recv_cb() lwIP wget
CVE-2026-74222 8.8 - High - September 29, 2026

U-Boot before 2026.10-rc5 contains a use-after-free vulnerability in the httpc_recv_cb() function within the lwIP wget implementation. When HTTP data storage fails, the callback frees the connection PCB but returns ERR_BUF instead of ERR_ABRT, causing the TCP input path to access released memory and crash the bootloader.

Dangling pointer

U-Boot <=2026.10-rc5 NFS Readlink Buffer Overflow
CVE-2026-74221 8.8 - High - September 29, 2026

U-Boot before 2026.10-rc5 contains a buffer overflow in nfs_readlink_reply() function in net/nfs-common.c when processing NFS server responses. A malicious NFS server can send crafted READLINK replies with negative or oversized symlink length values to corrupt memory and crash the bootloader.

Signed to Unsigned Conversion Error

U-Boot <2026.10-rc5 Buffer Overflow in nfs_read_reply()
CVE-2026-74220 8.8 - High - September 29, 2026

U-Boot before 2026.10-rc5 contains a buffer overflow in nfs_read_reply() function in net/nfs-common.c that allows attackers to corrupt memory by supplying crafted NFS READ reply lengths. A malicious NFS server can exploit signed integer handling to bypass length validation and write far past the destination buffer, crashing the bootloader or corrupting memory.

Signed to Unsigned Conversion Error

U-Boot <2026.10-rc3 IP_DEFRAG OOBW in __net_defragment()
CVE-2026-71971 8.8 - High - September 29, 2026

U-Boot before 2026.10-rc3 with CONFIG_IP_DEFRAG enabled contains an out-of-bounds write vulnerability in the __net_defragment() function in net/net.c. Remote attackers can send a crafted IP fragment with non-zero offset and More-Fragments flag set during netboot to corrupt adjacent memory and crash the bootloader.

Memory Corruption

Unbounded Memory Allocation in urllib3 HTTPResponse.read_chunked (1.10.3-2.8.0)
CVE-2026-97689 8.9 - High - September 29, 2026

urllib3 is an HTTP client library for Python. From 1.10.3 until 2.8.0, the HTTPResponse.read_chunked and HTTPResponse.stream methods can allocate unbounded memory because the streaming chunk parser buffers the chunk-size field until newline or EOF without a length bound. The trigger is that a malicious server returns Transfer-Encoding: chunked followed by a very long run of bytes without a newline. The attack mechanism is that a malicious HTTP server sends a very long unterminated chunk-size line. The impact is that unbounded memory allocation can exhaust the client process. This issue is fixed in version 2.8.0.

Allocation of Resources Without Limits or Throttling

OpenSSL QUIC stack no CID limit check 400MB memory exhaustion
CVE-2026-84784 7.5 - High - September 29, 2026

Issue summary: A malicious remote peer may flood the local QUIC stack with NEW_CONNECTION_ID frames by avoiding a limit check on how many connection IDs the remote QUIC stack can use. Impact summary: The local QUIC stack sends a RETIRE_CONN_ID frame for every NEW_CONNECTION_ID frame it receives. The RETIRE_CONN_ID frame is dispatched via the Control Frame Queue (CFQ). If the remote peer also withholds ACKs, then it can force the local stack to allocate ~400MB (depending on ACK delay). CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: RFC 9000 sections 5.1.1 and 5.1.2 [1] describe the mechanism by which a remote peer can notify the local QUIC stack to change the destination connection ID (a.k.a. CID) the local stack uses to identify the connection at the remote peer. Each CID is associated with a sequence number. The sequence number is transmitted in NEW_CONNECTION_ID and RETIRE_CONNECTION_ID frames to identify the CID which is being either associated with a connection or retired. The remote peer sends a NEW_CONNECTION_ID frame to let the local stack know a new CID is being associated with an existing connection. The NEW_CONNECTION_ID frame carries the new CID, its sequence number, and the retire-prior-to number. The retire-prior-to identifies existing CIDs that are to be retired. The local QUIC stack must send a RETIRE_CONNECTION_ID for every destination CID whose sequence number is less than retire-prior-to. The CID becomes retired after the local stack receives an ACK for its RETIRE_CONNECTION_ID frame. Although the OpenSSL QUIC stack supports at most one destination CID for every connection, it can be tricked into processing more than one RETIRE_CONNECTION_ID frame per connection. The OpenSSL QUIC stack currently retires the destination CID as soon as it receives the NEW_CONNECTION_ID, while in fact the destination CID must be retired after an ACK for the RETIRE_CONNECTION_ID frame is received. Correcting the flawed logic also fixes the backlog growth. [1] https://datatracker.ietf.org/doc/html/rfc9000#name-issuing-connection-ids FIPS impact: no The FIPS module is not affected as the QUIC implementation is outside of the OpenSSL FIPS module boundary.

Allocation of Resources Without Limits or Throttling

OpenSSL DTLS Out-of-Bounds Read via Suspended Write Retransmission
CVE-2026-84782 8.2 - High - September 29, 2026

Issue summary: The DTLS retransmission logic does not correctly handle a handshake message write that is suspended part-way through. The retransmitted message can be read past the message buffer and the retransmission overwrites the internal state the suspended write needs to resume correctly. Impact summary: The retransmitted message can disclose a heap memory to the peer as plaintext handshake data or cause a crash and a Denial of Service when the read reaches an unmapped memory region. CWE: CWE-125: Out-of-bounds Read Description: DTLS handshake messages can be written out in multiple fragments, and a write can suspend mid-message (returning WANT_WRITE) if the underlying transport temporarily cannot accept more data. While such a write is suspended, the DTLS retransmission timer may independently fire and ask the retransmission logic to resend an earlier, already-acknowledged-as-sent message from its retransmit queue. The retransmission logic reused the same internal buffer and position tracking as the message that was still being written, without resetting the position back to the start of the message being retransmitted. As a result the retransmission was read starting from wherever the suspended write had left off, producing a mislabelled message whose body was leftover bytes from the other, larger message still in flight - content that was never meant to be sent at that point, and which could run past the end of the allocated buffer. Separately, even when the retransmission is positioned correctly, allowing it to run to completion while another write is suspended overwrites the same shared bookkeeping that the suspended write depends on to resume. When the application later resumes the suspended write (via a subsequent SSL_read(), SSL_write(), SSL_accept(), or SSL_connect() call), it finds that bookkeeping in a state inconsistent with the message and aborts the process in a debugging build. The fix resets the retransmission's read position to the start of the message before resending, and skips retransmission entirely whenever a handshake write is still suspended, deferring to the next call that resumes it instead. FIPS impact: no The affected code is outside the FIPS module boundary.

Out-of-bounds Read

OpenSSL SM2 Signing Timing Side-Channel via Non-Constant Time Arithmetic
CVE-2026-77696 3.7 - Low - September 29, 2026

Issue summary: SM2 signature generation uses non-constant-time arithmetic on secret values, forming a timing side-channel. Impact summary: An attacker able to measure SM2 signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key. CWE: CWE-208: Observable Timing Discrepancy Description: SM2 signature generation computes the signature value using variable-time BIGNUM operations on the secret nonce and the private key, so the time taken to produce an SM2 signature depends on these secret values, forming a timing side-channel. Applications performing SM2 signature generation are affected on all platforms. FIPS Impact: no SM2 is not a FIPS algorithm.

Observable Timing Discrepancy

OpenSSL DTLS 1.2 AEAD CVE-2026-75806: Short Record DoS
CVE-2026-75806 5.3 - Medium - September 29, 2026

Issue summary: An established DTLS 1.2 association using an AEAD cipher suite can be terminated by a single unauthenticated datagram whose encrypted fragment is shorter than the mandatory explicit IV and authentication tag overhead. Impact summary: An attacker who can send a datagram that is routed to an existing DTLS 1.2 association can tear that association down without knowing any key material. This is a Denial of Service limited to the targeted association. There is no memory safety or confidentiality impact. CWE: CWE-1284: Improper Validation of Specified Quantity in Input Description: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher suite carries an explicit IV followed by the ciphertext and an authentication tag. When decrypting such a record the record layer passed the record length to the cipher implementation before checking that the record was long enough to contain the explicit IV and the tag. For a record shorter than that overhead the cipher implementation rejected the impossible length, and the record layer treated this as an internal failure and raised a fatal internal_error alert instead of treating the record as one that failed authentication. In TLS 1.2 the same record causes a fatal internal_error alert instead of the expected bad_record_mac alert. Since any undecryptable record already terminates a TLS connection, this is a protocol conformance issue rather than a security issue in TLS. The fix validates the record length against the explicit IV and tag length before any AEAD processing, so that TLS reports bad_record_mac and DTLS silently discards the record. FIPS impact: no The affected code is outside the FIPS module boundary.

Improper Validation of Specified Quantity in Input

OpenSSL CMP Client NULLPointer Deref via Crafted Revocation Response
CVE-2026-75805 5.3 - Medium - September 29, 2026

Issue summary: A CMP client that requests certificate revocation on the basis of a PKCS#10 CSR may dereference a NULL pointer and terminate abnormally when processing a crafted revocation response. Impact summary: The NULL pointer dereference happens on a read which leads to a crash and a Denial of Service for the affected client application. CWE: CWE-476: NULL-pointer dereference Description: A CMP client revoking a certificate has to tell the server which certificate to revoke, and may do so by supplying a PKCS#10 CSR instead of the certificate itself or its issuer name and serial number. This is 'openssl cmp -cmd rr -csr <file>' on the command line, or OSSL_CMP_exec_RR_ses() with the certificate supplied via OSSL_CMP_CTX_set1_p10CSR() through the API. A CSR does not contain the issuer name and serial number of the certificate, so the client does not send them. A server may optionally name the certificate it revoked in its response, and the client then compares that name against what it sent. Having sent neither an issuer name nor a serial number, it has nothing to compare against, and a server returning a specially crafted name causes the client to read from a NULL pointer and crash. The revocation response is checked for valid message protection before the affected code is reached, so an attacker must be a malicious or compromised CMP server, or a man-in-the-middle in possession of the secret used for message protection. Clients that identify the certificate to be revoked by a certificate or by issuer and serial number rather than by a PKCS#10 CSR are not affected. FIPS impact: no No FIPS modules are affected by this issue, as the CMP protocol implementation is outside the OpenSSL FIPS module boundary.

NULL Pointer Dereference

OPENSSL QUIC FC Bypass: 100MB Heap
CVE-2026-75804 5.3 - Medium - September 29, 2026

Issue summary: OpenSSL QUIC stack does not enforce connection level flow control for streams. Remote peers may send more bytes as long as they fit within the stream flow control limits. Impact summary: A malicious remote peer may exploit the lack of connection flow control for streams to make the QUIC stack receive ~100MB of memory instead of 768 KiB (default flow control window size). CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: The local QUIC stack advertises two flow control limits to its remote peer: stream flow control limit and connection flow control limit. The remote peer must follow both limits when transmitting stream data. Whenever the local QUIC stack receives a stream frame, it validates that the size of the received stream frame stays within flow control limits. If either limit is exceeded (stream level or connection level), then the QUIC stack must close the connection with a flow control error. The vulnerable OpenSSL QUIC stack enforces the stream-level but not the connection-level limit. To exploit the issue, three conditions must be met: - the remote peer opens several streams - each stream must stay within the stream-level flow control limit - there must be no zero-offset byte sent on any of the streams (to prevent the vulnerable QUIC stack from consuming data). By meeting the conditions above, the remote peer may make the local stack allocate 2 x MAX_STREAMS x (stream flow control limit) bytes of memory. MAX_STREAMS defaults to 100, and the limit applies to both bidirectional and unidirectional streams, making it 200 in total. The default flow control window for a stream is 512kB. The remote peer may force the vulnerable QUIC stack to allocate 100MB of heap per connection. FIPS impact: no The FIPS module is not affected as the QUIC implementation is outside of the OpenSSL FIPS module boundary.

Allocation of Resources Without Limits or Throttling

OpenSSL SSL_set_SSL_CTX TLS Context OOB Read/Write (4.0+)
CVE-2026-72897 7.5 - High - September 29, 2026

Issue summary: A TLS server that calls SSL_set_SSL_CTX() to switch a connection to a different SSL_CTX part way through a handshake may access memory beyond the end of an internal array if the replacement context knows about more provider signature algorithms than the context the connection was created from. Applications which never call SSL_set_SSL_CTX() are not affected. Impact summary: A remote peer may be able to cause a small out-of-bounds read, and in some circumstances a fixed-value out-of-bounds write, on the server heap. This may lead to a Denial of Service. CWE: CWE-787: Out-of-bounds Write Description: A TLS connection records how many certificate slots it has when it is created, taken from the SSL_CTX that created it: the built-in certificate types plus one slot for each provider TLS-SIGALG entry that context was aware of. That count sizes an internal array of per-slot certificate validity flags. An application may replace a connection's SSL_CTX part way through the handshake by calling SSL_set_SSL_CTX(), most commonly from a servername callback in order to serve a different virtual host. Doing so did not refresh the recorded count. A provider signature algorithm's slot index is its position in the list of whichever context resolves it, so if the replacement context is aware of more of them than the original, an algorithm offered by the peer can resolve to an index beyond the end of the array. Processing the peer's signature algorithms then reads one four byte word past the end for each such algorithm and, where the word read is zero, writes a fixed value over it. A peer offering many of them can corrupt heap metadata and abort the process. Only provider signature algorithms which occupy one of the excess slots, and which the server also has configured, have this effect. Codepoints the replacement context does not recognise are discarded without being resolved to a slot, and provider signature algorithms are usable only from TLS 1.3. The two contexts must therefore be aware of different numbers of provider signature algorithms, which requires separate library contexts, a provider loaded between the two being created, or providers which differ in what they advertise - in 4.0, for example, the default provider advertises SM2 where the FIPS provider does not. A deployment meeting the condition is also unable to negotiate the affected algorithms with legitimate clients, since the same stale count hides the corresponding certificates, so the misconfiguration is likely to be noticed. For that reason, and because the configuration is not the default, this issue has been assessed as Low severity. FIPS impact: no No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary.

Memory Corruption

urllib3 <2.8: Deflate Decoder Infinite Loop via Chunked Response HTTPResponse
CVE-2026-97688 6.9 - Medium - September 29, 2026

urllib3 is an HTTP client library for Python. From 2.6.2 until 2.8.0, HTTPResponse.stream and HTTPResponse.read_chunked can enter an infinite loop because the Deflate decoder retains trailing bytes as unconsumed input after reaching end-of-stream and repeatedly decodes them without progress. The issue occurs when an untrusted server sends a chunked Deflate response whose decoded body exceeds a positive finite chunk size and whose encoded body has trailing bytes, specifically a response with Transfer-Encoding: chunked and Content-Encoding: deflate, content decoding enabled, and the positive finite amt=N streaming chunk size. The attack mechanism is that a malicious server returns a compressed chunked response with trailing bytes after the Deflate stream. The impact is excessive CPU usage and a request that does not complete, and network read timeouts do not interrupt the loop because no further socket read occurs. This issue is fixed in version 2.8.0.

Infinite Loop

OpenSSL SM2 Scalar Mult. Timing Leak on ARM64/RISC-V (4.0.0)
CVE-2026-54875 3.7 - Low - September 29, 2026

Issue summary: A non-constant-time optimized implementation of scalar point multiplication is used for SM2 private key operations on ARM64 and RISC-V platforms. Impact summary: An attacker able to measure the time taken by, or to observe the cache-line access pattern of SM2 signing or decryption on an affected platform can learn information about the secret scalar. CWE: CWE-208: Observable Timing Discrepancy Description: On ARM64 and RISC-V processors, the SM2 curve uses an optimized scalar multiplication implementation whose conditional branches and table look ups are chosen according to the bits of the secret scalar. The execution time and the cache-access pattern therefore depend on the long-term private key (during SM2 decryption) or the per-signature nonce (during SM2 signature generation), forming a timing and cache side-channel. FIPS Impact: no SM2 is not a FIPS algorithm and the optimized SM2 implementation is not part of the FIPS module. OpenSSL 4.0, 3.6, 3.5 and 3.4 are vulnerable to this issue on AArch64 and RISC-V. OpenSSL 3.0, 1.1.1 and 1.0.2 are not affected by this issue. OpenSSL 4.0 users should upgrade to OpenSSL 4.0.3. OpenSSL 3.6 users should upgrade to OpenSSL 3.6.5. OpenSSL 3.5 users should upgrade to OpenSSL 3.5.9. OpenSSL 3.4 users should upgrade to OpenSSL 3.4.8. This issue was reported on 2 May 2026 by Abhinav Agarwal. It was independently reported on 6 June 2026 by Feng Xue. The fix was developed by Igor Ustinov. -- cut (non-publishing metadata for internal use) -- Reported by: Abhinav Agarwal, Feng Xue Fixed by: Igor Ustinov

Observable Timing Discrepancy

OpenSSL QUIC Stack Memory Overcommit via Long-Lived Buffers
CVE-2026-54873 7.5 - High - September 29, 2026

Issue summary: QUIC process may keep memory for QUIC packet buffer for much longer period than necessary. Impact summary: Remote peer can exploit this vulnerability by sending maliciously crafted packets, making the local QUIC stack to keep the memory for packet buffers allocated. The time for which the memory remains allocated is entirely under the control of the potentially malicious remote peer. CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: To save copy operation from the packet buffer to the stream reassemble buffer the QUIC stack leaves the stream data on the packet buffer waiting to be copied to a buffer provided by the local receiving application. The QUIC stack releases a reference to the packet buffer only after the data are copied to the application buffer. This design is more efficient for legitimate data transfers but enables an attacker to allocate a lot more memory than actually required by the data kept in the receiving stream buffer. To mitigate the vulnerability, the QUIC stack now calculates and monitors memory overhead for every stream. The memory overhead for a single stream frame is calculated as a difference between the size of the whole packet that carries the stream frame and the size of the stream frame itself. The memory overhead for a single stream frame is added to the total (cumulative) memory overhead QUIC stack keeps for each stream. Once the cumulative memory overhead exceeds 64kB, the QUIC stack moves the stream frame data from the packet buffer to the stream buffer, starting with the next packet received. FIPS impact: no The FIPS module is not affected as the QUIC implementation is outside of the OpenSSL FIPS module boundary.

Allocation of Resources Without Limits or Throttling

OpenSSL: Generic EC Scalar Mul Timing Leak Exposes ECDSA/SM2 Nonce
CVE-2026-54872 3.7 - Low - September 29, 2026

Issue summary: The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves that do not have a dedicated implementation leaks information about the secret nonce through timing. Impact summary: An attacker able to measure signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key. CWE: CWE-208: Observable Timing Discrepancy Description: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce. The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1. Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue. The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected. FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path.

Observable Timing Discrepancy

OpenSSL QUIC: Stream Reassembly O(n^2) CPU DoS via Out-of-Order Frames
CVE-2026-42772 5.3 - Medium - September 29, 2026

Issue summary: The QUIC stream reassembly algorithm performance deteriorates progressively as packets are arriving out of order. The worst case has a quadratic complexity proportional to the number of stream frames kept in the buffer for the received stream data. Impact summary: A remote QUIC peer that completes the handshake can create a connection-scoped CPU pressure and potentially a Denial of Service using compliant STREAM frames inside the advertised receive window, with low attacker bandwidth. CWE: CWE-407: Inefficient Algorithmic Complexity Description: OpenSSL manages received QUIC stream fragments using a doubly-linked list. While it optimizes for append operations (at the end of the list), it falls back to a head-to-tail linear search for any fragment that does not immediately follow the current `tail`. By manipulating the sequence of offsets, an attacker can force the server to perform O(n^2) operations, consuming excessive CPU time for the QUIC process. FIPS impact: no The FIPS module is not affected as the QUIC implementation is outside of the OpenSSL FIPS module boundary.

Inefficient Algorithmic Complexity

OpenSSL QUIC Server Amplification via Unvalidated Credit Computation
CVE-2026-35191 3.7 - Low - September 29, 2026

Issue summary: The OpenSSL QUIC server, when configured to not preform address validation, can be forced to count incoming packets multiple times in its unvalidated credit computation, leading to a violation of the RFC 9000 unvalidated connection amplification limit of 3 times the amount of data received. Impact summary: A remote attacker able to spoof packets to a server using the OpenSSL QUIC implementation might use the server for an amplification of a DDoS attack. CWE: CWE-440: Expected Behavior Violation Description: OpenSSL's QUIC stack, when operating as a server, enforces client address validation (RFC 9000, Section 8), to confirm the peer address is not used for a traffic amplification attack. If this feature is disabled on the server, the QUIC stack limits the amount of server data that can be sent to 3 times the amount of data received from the peer address, until such time as the TLS handshake is completed. The OpenSSL QUIC server, when operating in non-validation mode, adds the length of the whole datagram received to the unvalidated credit limit when processing each QUIC packet in the datagram. A remote peer may, after establishing a connection with an initial client hello frame, send a subsequent datagram containing multiple QUIC packets, leading the server to account the entire datagram length for each packet in the datagram, resulting in the server believing that the peer has sent more data than it actually has, thereby violating the 3x amplification limit mandated by the RFC. FIPS impact: no As the QUIC stack lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.

Expected Behavior Violation

OpenSSL CRL DP Heap DoS via nameRelativeToCRLIssuer
CVE-2026-35189 5.3 - Medium - September 29, 2026

Issue summary: A certificate with many nameRelativeToCRLIssuer CRL distribution points causes disproportionate heap growth when OpenSSL caches X.509 extensions. Impact summary: Receiving a crafted certificate from a malicious peer can lead to significant memory pressure and possible Denial of Service in clients or in servers that solicit client certificates. CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: A certificate or a set of certificates that fits under the limit for size of certificates accepted from the peer (~100 KiB) can result in allocation of several hundred MiB of resident memory on the receiving side during a normal TLS handshake. This may be enough to crash the client or server, if multiple concurrent connections lead to similarly large memory allocations. The fix postpones processing of the CRL distribution points extensions in certificates to the time when the processed value is required for CRL processing. This avoids keeping large memory allocations for a long time when such certificates are received. FIPS impact: no The affected code is outside the FIPS module boundary.

Allocation of Resources Without Limits or Throttling

urllib3 TLS Proxy Context Separation Flaw (1.26.0-2.8.0)
CVE-2026-97687 7.6 - High - September 29, 2026

urllib3 is an HTTP client library for Python. From 1.26.0 until 2.8.0, the proxy_ssl_context, proxy_assert_hostname, proxy_assert_fingerprint, ssl_context, cert_reqs, verify_mode, use_forwarding_for_https=True, and CERT_NONE configuration paths fail to remain separated because target-server TLS settings are incorrectly applied to the HTTPS proxy connection. The trigger is that an application uses an HTTPS proxy and configures target-server TLS settings that must remain separate from the proxy TLS handshake, including HTTPS forwarding with target-specific identity or credentials. Applying cert_reqs=CERT_NONE can overwrite proxy_ssl_context.verify_mode in place, and the mutation persists so later connections reusing the same context may connect to the HTTPS proxy without certificate verification. The attack mechanism is that an attacker intercepts and impersonates the HTTPS proxy after the effective proxy policy accepts the attacker's certificate. The impact is that the attacker can observe or modify forwarded traffic or receive a target TLS client certificate, while CONNECT tunneling still preserves the separate end-to-end target TLS connection. This issue is fixed in version 2.8.0.

Improper Certificate Validation

Das U-Boot IP Reassembly State Leak Arbitrary Code via IP Fragments
CVE-2026-15390 9 - Critical - September 29, 2026

Das U-Boot with CONFIG_IP_DEFRAG=y parameter fails to clear IP reassembly state after delivering a complete datagram. An attacker who can deliver fragmented IP traffic can execute arbitrary code by sending duplicated last-fragment IP packets. This issue was fixed in commit b1aec609bb5e0d08c25c888c91935287ab4ee5fa in version 2026.07.

Memory Corruption

Perl DBI <1.654: FetchHashKeyName can cause SegFault (CVE-2026-88816)
CVE-2026-88816 7.5 - High - September 28, 2026

DBI versions before 1.654 for Perl incorrectly treat numeric values as strings in FetchHashKeyName. fetchrow_hashref uses the string pointer of the FetchHashKeyName attribute as the key name without stringifying it first. When FetchHashKeyName has been set to an integer (IV) or floating-point (NV) value, that pointer is invalid, so reading the key name triggers a segmentation fault. This can be triggered with the following code: my $dbh = DBI->connect( "dbi:ExampleP:", "", "", { RaiseError => 0, PrintError => 0 } ); $dbh->{FetchHashKeyName} = 42; my $sth = $dbh->prepare("select mode, size, name from ."); $sth->execute; $sth->fetchrow_hashref;

Object Type Confusion

libX11 <=1.8.13 OOB Read via Codeset Parser (xorg)
CVE-2026-94285 5.1 - Medium - September 28, 2026

An out-of-bounds read in libX11's byte-oriented codeset parser in libX11 before 1.8.14 could be used by malicious X servers to crash attached X clients.

Out-of-bounds Read

Out-of-Bounds Read in libX11 XIM Trigger-Key Parser (before 1.8.14)
CVE-2026-94284 5.5 - Medium - September 28, 2026

An out-of-bounds read vulnerability in libX11's XIM trigger-key registration parser in libX11 before 1.8.14 could be used by malicious X servers to crash attached X clients.

Out-of-bounds Read

libX11 OOB Read via XIM Atr Parser <1.8.14 (CVE-2026-94283)
CVE-2026-94283 6.5 - Medium - September 28, 2026

An out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser in libX11 before 1.8.14 could be used by malicious X servers to crash attached X clients.

Out-of-bounds Read