Canonical Linux software

Recent Canonical Security Advisories

By the Year

In 2026 there have been 483 vulnerabilities in Canonical with an average score of 6.4 out of ten. Last year, in 2025 Canonical had 2884 security vulnerabilities published. Right now, Canonical is on track to have less security vulnerabilities in 2026 than it did last year. However, the average CVE base score of the vulnerabilities in 2026 is greater by 0.11.

Recent Canonical Security Vulnerabilities

CVE	Date	Vulnerability	Products
CVE-2026-6970	Apr 27, 2026	authd <=0.6.3 LPE via GID misassignment bug authd prior to version 0.6.4 contains a logic error in primary group ID assignment that can lead to local privilege escalation. When a user's primary group ID (GID) differs from their UID, either because the account was created with authd prior to version 0.5.4 or because the primary group was manually changed via the `authctl group set-gid` command, and the user's identity provider record is updated, authd incorrectly resets the user's primary group ID to their UID upon next login. This causes newly created files and directories to be owned by the wrong group, causing denial of service issues, and potentially granting unintended access to other local users and allowing local privilege escalation.
CVE-2026-40372	Apr 21, 2026	Apr 2026: ASP.NET Core Elevation of Privilege Vulnerability Improper verification of cryptographic signature in ASP.NET Core allows an unauthorized attacker to elevate privileges over a network.	Ubuntu Linux
CVE-2026-6369	Apr 20, 2026	Canonical Livepatch Snap Client <10.15.0 Improper Access Control for Root Token An improper access control vulnerability in the canonical-livepatch snap client prior to version 10.15.0 allows a local unprivileged user to obtain a sensitive, root-level authentication token by sending an unauthenticated request to the livepatchd.sock Unix domain socket. This vulnerability is exploitable on systems where an administrator has already enabled the Livepatch client with a valid Ubuntu Pro subscription. This token allows an attacker to access Livepatch services using the victim's credentials, as well as potentially cause issues to the Livepatch server.
CVE-2026-26171	Apr 14, 2026	Apr 2026: .NET Denial of Service Vulnerability Uncontrolled resource consumption in .NET allows an unauthorized attacker to deny service over a network.	Ubuntu Linux
CVE-2026-32203	Apr 14, 2026	Apr 2026: .NET and Visual Studio Denial of Service Vulnerability Stack-based buffer overflow in .NET and Visual Studio allows an unauthorized attacker to deny service over a network.	Ubuntu Linux
CVE-2026-33116	Apr 14, 2026	Apr 2026: .NET, .NET Framework, and Visual Studio Denial of Service Vulnerability Loop with unreachable exit condition ('infinite loop') in .NET, .NET Framework, Visual Studio allows an unauthorized attacker to deny service over a network.	Ubuntu Linux
CVE-2026-32178	Apr 14, 2026	Apr 2026: .NET Spoofing Vulnerability Improper neutralization of special elements in .NET allows an unauthorized attacker to perform spoofing over a network.	Ubuntu Linux
CVE-2026-33948	Apr 13, 2026	jq NUL byte validation bypass enabling parser differential attack jq is a command-line JSON processor. Commits before 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b contain a vulnerability where CLI input parsing allows validation bypass via embedded NUL bytes. When reading JSON from files or stdin, jq uses strlen() to determine buffer length instead of the actual byte count from fgets(), causing it to truncate input at the first NUL byte and parse only the preceding prefix. This enables an attacker to craft input with a benign JSON prefix before a NUL byte followed by malicious trailing data, where jq validates only the prefix as valid JSON while silently discarding the suffix. Workflows relying on jq to validate untrusted JSON before forwarding it to downstream consumers are susceptible to parser differential attacks, as those consumers may process the full input including the malicious trailing bytes. This issue has been patched by commit 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b.	Ubuntu Linux
CVE-2026-40164	Apr 13, 2026	jq DoS via Hash Collision Exploit jq is a command-line JSON processor. Before commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq used MurmurHash3 with a hardcoded, publicly visible seed (0x432A9843) for all JSON object hash table operations, which allowed an attacker to precompute key collisions offline. By supplying a crafted JSON object (~100 KB) where all keys hashed to the same bucket, hash table lookups degraded from O(1) to O(n), turning any jq expression into an O(n²) operation and causing significant CPU exhaustion. This affected common jq use cases such as CI/CD pipelines, web services, and data processing scripts, and was far more practical to exploit than existing heap overflow issues since it required only a small payload. This issue has been patched in commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784.	Ubuntu Linux
CVE-2026-39979	Apr 13, 2026	jq libjq buffer overflow in jv_parse_sized() (CVE-2026-39979) jq is a command-line JSON processor. In commits before 2f09060afab23fe9390cce7cb860b10416e1bf5f, the jv_parse_sized() API in libjq accepts a counted buffer with an explicit length parameter, but its error-handling path formats the input buffer using %s in jv_string_fmt(), which reads until a NUL terminator is found rather than respecting the caller-supplied length. This means that when malformed JSON is passed in a non-NUL-terminated buffer, the error construction logic performs an out-of-bounds read past the end of the buffer. The vulnerability is reachable by any libjq consumer calling jv_parse_sized() with untrusted input, and depending on memory layout, can result in memory disclosure or process termination. The issue has been patched in commit 2f09060afab23fe9390cce7cb860b10416e1bf5f.	Ubuntu Linux
CVE-2026-39956	Apr 13, 2026	CLI jq Crash via Unchecked StrIndices: Runtime Failure & Ptr Read jq is a command-line JSON processor. In commits after 69785bf77f86e2ea1b4a20ca86775916889e91c9, the _strindices builtin in jq's src/builtin.c passes its arguments directly to jv_string_indexes() without verifying they are strings, and jv_string_indexes() in src/jv.c relies solely on assert() checks that are stripped in release builds compiled with -DNDEBUG. This allows an attacker to crash jq trivially with input like _strindices(0), and by crafting a numeric value whose IEEE-754 bit pattern maps to a chosen pointer, achieve a controlled pointer dereference and limited memory read/probe primitive. Any deployment that evaluates untrusted jq filters against a release build is vulnerable. This issue has been patched in commit fdf8ef0f0810e3d365cdd5160de43db46f57ed03.	Ubuntu Linux
CVE-2026-33947	Apr 13, 2026	jq <=1.8.1 Unbounded Recursion Crash via setpath/getpath jq is a command-line JSON processor. In versions 1.8.1 and below, functions jv_setpath(), jv_getpath(), and delpaths_sorted() in jq's src/jv_aux.c use unbounded recursion whose depth is controlled by the length of a caller-supplied path array, with no depth limit enforced. An attacker can supply a JSON document containing a flat array of ~65,000 integers (~200 KB) that, when used as a path argument by a trusted jq filter, exhausts the C call stack and crashes the process with a segmentation fault (SIGSEGV). This bypass works because the existing MAX_PARSING_DEPTH (10,000) limit only protects the JSON parser, not runtime path operations where arrays can be programmatically constructed to arbitrary lengths. The impact is denial of service (unrecoverable crash) affecting any application or service that processes untrusted JSON input through jq's setpath, getpath, or delpaths builtins. This issue has been addressed in commit fb59f1491058d58bdc3e8dd28f1773d1ac690a1f.	Ubuntu Linux
CVE-2026-32316	Apr 13, 2026	Integer Overflow in jq 1.8.1 via jvp_string_* Heap Buffer Overflow jq is a command-line JSON processor. An integer overflow vulnerability exists through version 1.8.1 within the jvp_string_append() and jvp_string_copy_replace_bad functions, where concatenating strings with a combined length exceeding 2^31 bytes causes a 32-bit unsigned integer overflow in the buffer allocation size calculation, resulting in a drastically undersized heap buffer. Subsequent memory copy operations then write the full string data into this undersized buffer, causing a heap buffer overflow classified as CWE-190 (Integer Overflow) leading to CWE-122 (Heap-based Buffer Overflow). Any system evaluating untrusted jq queries is affected, as an attacker can crash the process or potentially achieve further exploitation through heap corruption by crafting queries that produce extremely large strings. The root cause is the absence of string size bounds checking, unlike arrays and objects which already have size limits. The issue has been addressed in commit e47e56d226519635768e6aab2f38f0ab037c09e5.	Ubuntu Linux
CVE-2026-5412	Apr 10, 2026	Juju <2.9.57, 3.6.21: Auth flaw in Controller facade leaks cloud creds In Juju versions prior to 2.9.57 and 3.6.21, an authorization issue exists in the Controller facade. An authenticated user can call the CloudSpec API method to extract the cloud credentials used to bootstrap the controller. This allows a low-privileged user to access sensitive credentials. This issue is resolved in Juju versions 2.9.57 and 3.6.21.
CVE-2026-5774	Apr 10, 2026	Juju 4.0.5/3.6.20/2.9.56 API: Improper userTokens sync allows DoS or token reuse Improper synchronization of the userTokens map in the API server in Canonical Juju 4.0.5, 3.6.20, and 2.9.56 may allow an authenticated user to possibly cause a denial of service on the server or possibly reuse a single-use discharge token.
CVE-2025-14551	Apr 09, 2026	Subiquity 24.04.4 Wi-Fi Password Leak in Crash Reports In Ubuntu, Subiquity version 24.04.4 could leak sensitive user credentials during crash reporting. Upon installation failure, if a user submitted a bug report to Launchpad, Subiquity could include certain user credentials, such as the user's plaintext Wi-Fi password, in the attached logs.
CVE-2025-15480	Apr 09, 2026	Ubuntu-Desktop-Provision 24.04.4 Credentials Leak via Crash Report In Ubuntu, ubuntu-desktop-provision version 24.04.4 could leak sensitive user credentials during crash reporting. Upon installation failure, if a user submitted a bug report to Launchpad, ubuntu-desktop-provision could include the user's password hash in the attached logs.
CVE-2026-34179	Apr 09, 2026	Canonical LXD 4.126.7: Type Field Bypass Admin Escalation (CVE202634179) In Canonical LXD versions 4.12 through 6.7, the doCertificateUpdate function in lxd/certificates.go does not validate the Type field when handling PUT/PATCH requests to /1.0/certificates/{fingerprint} for restricted TLS certificate users, allowing a remote authenticated attacker to escalate privileges to cluster admin.	Lxd
CVE-2026-34178	Apr 09, 2026	LXD <6.8 backup import: Project restriction bypass (CVE-2026-34178) In Canonical LXD before 6.8, the backup import path validates project restrictions against backup/index.yaml in the supplied tar archive but creates the instance from backup/container/backup.yaml, a separate file in the same archive that is never checked against project restrictions. An authenticated remote attacker with instance-creation permission in a restricted project can craft a backup archive where backup.yaml carries restricted settings such as security.privileged=true or raw.lxc directives, bypassing all project restriction enforcement and allowing full host compromise.	Lxd
CVE-2026-34177	Apr 09, 2026	LXD 4.126.7 PrivEsc: Missing denylist for raw.apparmor & raw.qemu.conf in isVMLowLevelOptionForbidde Canonical LXD versions 4.12 through 6.7 contain an incomplete denylist in isVMLowLevelOptionForbidden (lxd/project/limits/permissions.go), which omits raw.apparmor and raw.qemu.conf from the set of keys blocked under the restricted.virtual-machines.lowlevel=block project restriction. A remote attacker with can_edit permission on a VM instance in a restricted project can inject an AppArmor rule and a QEMU chardev configuration that bridges the LXD Unix socket into the guest VM, enabling privilege escalation to LXD cluster administrator and subsequently to host root.	Lxd
CVE-2026-39881	Apr 08, 2026	Vim 9.2.0316 Cmd Injection via NetBeans Intf Vim is an open source, command line text editor. Prior to 9.2.0316, a command injection vulnerability in Vim's netbeans interface allows a malicious netbeans server to execute arbitrary Ex commands when Vim connects to it, via unsanitized strings in the defineAnnoType and specialKeys protocol messages. This vulnerability is fixed in 9.2.0316.	Ubuntu Linux
CVE-2026-31790	Apr 07, 2026	OpenSSL 3.6+ RSA KEM Buffer Leak via EVP_PKEY_encapsulate Issue summary: Applications using RSASVE key encapsulation to establish a secret encryption key can send contents of an uninitialized memory buffer to a malicious peer. Impact summary: The uninitialized buffer might contain sensitive data from the previous execution of the application process which leads to sensitive data leakage to an attacker. RSA_public_encrypt() returns the number of bytes written on success and -1 on error. The affected code tests only whether the return value is non-zero. As a result, if RSA encryption fails, encapsulation can still return success to the caller, set the output lengths, and leave the caller to use the contents of the ciphertext buffer as if a valid KEM ciphertext had been produced. If applications use EVP_PKEY_encapsulate() with RSA/RSASVE on an attacker-supplied invalid RSA public key without first validating that key, then this may cause stale or uninitialized contents of the caller-provided ciphertext buffer to be disclosed to the attacker in place of the KEM ciphertext. As a workaround calling EVP_PKEY_public_check() or EVP_PKEY_public_check_quick() before EVP_PKEY_encapsulate() will mitigate the issue. The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.1 and 3.0 are affected by this issue.	Ubuntu Linux
CVE-2026-31789	Apr 07, 2026	OpenSSL X.509 OCTET STRINGHeap overflow on 32-bit Issue summary: Converting an excessively large OCTET STRING value to a hexadecimal string leads to a heap buffer overflow on 32 bit platforms. Impact summary: A heap buffer overflow may lead to a crash or possibly an attacker controlled code execution or other undefined behavior. If an attacker can supply a crafted X.509 certificate with an excessively large OCTET STRING value in extensions such as the Subject Key Identifier (SKID) or Authority Key Identifier (AKID) which are being converted to hex, the size of the buffer needed for the result is calculated as multiplication of the input length by 3. On 32 bit platforms, this multiplication may overflow resulting in the allocation of a smaller buffer and a heap buffer overflow. Applications and services that print or log contents of untrusted X.509 certificates are vulnerable to this issue. As the certificates would have to have sizes of over 1 Gigabyte, printing or logging such certificates is a fairly unlikely operation and only 32 bit platforms are affected, this issue was assigned Low severity. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.	Ubuntu Linux
CVE-2026-28390	Apr 07, 2026	OpenSSL CMS NULL Deref via KeyTransportRecipientInfo before 3.6 Issue summary: During processing of a crafted CMS EnvelopedData message with KeyTransportRecipientInfo a NULL pointer dereference can happen. Impact summary: Applications that process attacker-controlled CMS data may crash before authentication or cryptographic operations occur resulting in Denial of Service. When a CMS EnvelopedData message that uses KeyTransportRecipientInfo with RSA-OAEP encryption is processed, the optional parameters field of RSA-OAEP SourceFunc algorithm identifier is examined without checking for its presence. This results in a NULL pointer dereference if the field is missing. Applications and services that call CMS_decrypt() on untrusted input (e.g., S/MIME processing or CMS-based protocols) are vulnerable. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.	Ubuntu Linux
CVE-2026-28389	Apr 07, 2026	OpenSSL 3.x CMS NULL Deref via KeyAgreeRecipientInfo in EnvelopedData Issue summary: During processing of a crafted CMS EnvelopedData message with KeyAgreeRecipientInfo a NULL pointer dereference can happen. Impact summary: Applications that process attacker-controlled CMS data may crash before authentication or cryptographic operations occur resulting in Denial of Service. When a CMS EnvelopedData message that uses KeyAgreeRecipientInfo is processed, the optional parameters field of KeyEncryptionAlgorithmIdentifier is examined without checking for its presence. This results in a NULL pointer dereference if the field is missing. Applications and services that call CMS_decrypt() on untrusted input (e.g., S/MIME processing or CMS-based protocols) are vulnerable. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.	Ubuntu Linux
CVE-2026-28388	Apr 07, 2026	OpenSSL Delta CRL Indicator NPE CVE-2026-28388 Issue summary: When a delta CRL that contains a Delta CRL Indicator extension is processed a NULL pointer dereference might happen if the required CRL Number extension is missing. Impact summary: A NULL pointer dereference can trigger a crash which leads to a Denial of Service for an application. When CRL processing and delta CRL processing is enabled during X.509 certificate verification, the delta CRL processing does not check whether the CRL Number extension is NULL before dereferencing it. When a malformed delta CRL file is being processed, this parameter can be NULL, causing a NULL pointer dereference. Exploiting this issue requires the X509_V_FLAG_USE_DELTAS flag to be enabled in the verification context, the certificate being verified to contain a freshestCRL extension or the base CRL to have the EXFLAG_FRESHEST flag set, and an attacker to provide a malformed CRL to an application that processes it. The vulnerability is limited to Denial of Service and cannot be escalated to achieve code execution or memory disclosure. For that reason the issue was assessed as Low severity according to our Security Policy. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.	Ubuntu Linux
CVE-2026-28387	Apr 07, 2026	OpenSSL DANE TLSA UAF Vulnerability Issue summary: An uncommon configuration of clients performing DANE TLSA-based server authentication, when paired with uncommon server DANE TLSA records, may result in a use-after-free and/or double-free on the client side. Impact summary: A use after free can have a range of potential consequences such as the corruption of valid data, crashes or execution of arbitrary code. However, the issue only affects clients that make use of TLSA records with both the PKIX-TA(0/PKIX-EE(1) certificate usages and the DANE-TA(2) certificate usage. By far the most common deployment of DANE is in SMTP MTAs for which RFC7672 recommends that clients treat as 'unusable' any TLSA records that have the PKIX certificate usages. These SMTP (or other similar) clients are not vulnerable to this issue. Conversely, any clients that support only the PKIX usages, and ignore the DANE-TA(2) usage are also not vulnerable. The client would also need to be communicating with a server that publishes a TLSA RRset with both types of TLSA records. No FIPS modules are affected by this issue, the problem code is outside the FIPS module boundary.	Ubuntu Linux
CVE-2026-33034	Apr 07, 2026	CVE-2026-33034: Django 4.2-6.0 b4 upload size limit bypass (ASGI) An issue was discovered in 6.0 before 6.0.4, 5.2 before 5.2.13, and 4.2 before 4.2.30. ASGI requests with a missing or understated `Content-Length` header could bypass the `DATA_UPLOAD_MAX_MEMORY_SIZE` limit when reading `HttpRequest.body`, allowing remote attackers to load an unbounded request body into memory. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank Superior for reporting this issue.	Ubuntu Linux
CVE-2026-33033	Apr 07, 2026	Django 4.2~4.2.30,5.2~5.2.13,6.0~6.0.4 MP Degrade via Base64 Whitespace An issue was discovered in 6.0 before 6.0.4, 5.2 before 5.2.13, and 4.2 before 4.2.30. `MultiPartParser` allows remote attackers to degrade performance by submitting multipart uploads with `Content-Transfer-Encoding: base64` including excessive whitespace. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank Seokchan Yoon for reporting this issue.	Ubuntu Linux
CVE-2026-4292	Apr 07, 2026	Django Admin list_editable POST injection allows new instances <=6.0.3 An issue was discovered in 6.0 before 6.0.4, 5.2 before 5.2.13, and 4.2 before 4.2.30. Admin changelist forms using `ModelAdmin.list_editable` incorrectly allowed new instances to be created via forged `POST` data. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank Cantina for reporting this issue.	Ubuntu Linux
CVE-2026-4277	Apr 07, 2026	Django GenericInlineModelAdmin Permissions Bypass in 4.2<4.2.30,5.2<5.2.13,6.0<6.0.4 An issue was discovered in 6.0 before 6.0.4, 5.2 before 5.2.13, and 4.2 before 4.2.30. Add permissions on inline model instances were not validated on submission of forged `POST` data in `GenericInlineModelAdmin`. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank N05ec@LZU-DSLab for reporting this issue.	Ubuntu Linux
CVE-2026-3902	Apr 07, 2026	Header Spoofing in Django ASGIRequest 4.2-6.0 (6.0.4, 5.2.13, 4.2.30) An issue was discovered in 6.0 before 6.0.4, 5.2 before 5.2.13, and 4.2 before 4.2.30. `ASGIRequest` allows a remote attacker to spoof headers by exploiting an ambiguous mapping of two header variants (with hyphens or with underscores) to a single version with underscores. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank Tarek Nakkouch for reporting this issue.	Ubuntu Linux
CVE-2026-35177	Apr 06, 2026	Path Traversal Bypass in Vim zip.vim before 9.2.0280 (CVE-2026-35177) Vim is an open source, command line text editor. Prior to 9.2.0280, a path traversal bypass in Vim's zip.vim plugin allows overwriting of arbitrary files when opening specially crafted zip archives, circumventing the previous fix for CVE-2025-53906. This vulnerability is fixed in 9.2.0280.	Ubuntu Linux
CVE-2026-34982	Apr 06, 2026	Vim <9.2.0276 Modeline Sandbox Bypass OS Command Exec Vim is an open source, command line text editor. Prior to version 9.2.0276, a modeline sandbox bypass in Vim allows arbitrary OS command execution when a user opens a crafted file. The `complete`, `guitabtooltip` and `printheader` options are missing the `P_MLE` flag, allowing a modeline to be executed. Additionally, the `mapset()` function lacks a `check_secure()` call, allowing it to be abused from sandboxed expressions. Commit 9.2.0276 fixes the issue.	Ubuntu Linux
CVE-2026-35536	Apr 03, 2026	Tornado 6.5.5+ vulnerability: RequestHandler cookie attr injection via set_cookie In Tornado before 6.5.5, cookie attribute injection could occur because the domain, path, and samesite arguments to .RequestHandler.set_cookie were not checked for crafted characters.	Ubuntu Linux
CVE-2026-26962	Apr 02, 2026	Rack 3.2.03.2.5 Header Injection via Incorrect Multipart Header Unfolding Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting. This issue has been patched in version 3.2.6.	Ubuntu Linux
CVE-2026-34835	Apr 02, 2026	Rack Host Header Poisoning via INVALID HOST chars (<3.1.21, <3.2.6) Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, #, and @. Because req.host returns the full parsed value, applications that validate hosts using naive prefix or suffix checks can be bypassed. This can lead to host header poisoning in applications that use req.host, req.url, or req.base_url for link generation, redirects, or origin validation. This issue has been patched in versions 3.1.21 and 3.2.6.	Ubuntu Linux
CVE-2026-35414	Apr 02, 2026	OpenSSH 10.2 Principals Option Misparse via Commas in CA OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list in conjunction with a Certificate Authority that makes certain use of comma characters.	Ubuntu Linux
CVE-2026-34827	Apr 02, 2026	Rack 3.0.01-3.1.20/3.2.0-3.2.5 DOS via Escaped Multipart Parameters Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Multipart::Parser#handle_mime_head parses quoted multipart parameters such as Content-Disposition: form-data; name="..." using repeated String#index searches combined with String#slice! prefix deletion. For escape-heavy quoted values, this causes super-linear processing. An unauthenticated attacker can send a crafted multipart/form-data request containing many parts with long backslash-escaped parameter values to trigger excessive CPU usage during multipart parsing. This results in a denial of service condition in Rack applications that accept multipart form data. This issue has been patched in versions 3.1.21 and 3.2.6.	Ubuntu Linux
CVE-2026-32762	Apr 02, 2026	Rack::Utils.forwarded_values RFC7239 Parsing Flaw <3.1.21 & <3.2.6 Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21 and 3.2.0 to before 3.2.6, Rack::Utils.forwarded_values parses the RFC 7239 Forwarded header by splitting on semicolons before handling quoted-string values. Because quoted values may legally contain semicolons, a header can be interpreted by Rack as multiple Forwarded directives rather than as a single quoted for value. In deployments where an upstream proxy, WAF, or intermediary validates or preserves quoted Forwarded values differently, this discrepancy can allow an attacker to smuggle host, proto, for, or by parameters through a single header value. This issue has been patched in versions 3.1.21 and 3.2.6.	Ubuntu Linux
CVE-2026-35388	Apr 02, 2026	OpenSSH <10.3: Missing confirmation in proxymode multiplexing OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.	Ubuntu Linux
CVE-2026-35387	Apr 02, 2026	OpenSSH <10.3 Unintended ECDSA via PubkeyAcceptedAlgorithms OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.	Ubuntu Linux
CVE-2026-34830	Apr 02, 2026	Regex Injection via X-Accel-Mapping in Rack::Sendfile 3.2.6 Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Sendfile#map_accel_path interpolates the value of the X-Accel-Mapping request header directly into a regular expression when rewriting file paths for X-Accel-Redirect. Because the header value is not escaped, an attacker who can supply X-Accel-Mapping to the backend can inject regex metacharacters and control the generated X-Accel-Redirect response header. In deployments using Rack::Sendfile with x-accel-redirect, this can allow an attacker to cause nginx to serve unintended files from configured internal locations. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.	Ubuntu Linux
CVE-2026-34829	Apr 02, 2026	Rack Multipart::Parser Unbounded Disk Usage DOS in <2.2.23, <3.1.21, <3.2.6 Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser only wraps the request body in a BoundedIO when CONTENT_LENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size limit. For file parts, the uploaded body is written directly to a temporary file on disk rather than being constrained by the buffered in-memory upload limit. An unauthenticated attacker can therefore stream an arbitrarily large multipart file upload and consume unbounded disk space. This results in a denial of service condition for Rack applications that accept multipart form data. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.	Ubuntu Linux
CVE-2026-34826	Apr 02, 2026	Rack::Utils.get_byte_ranges DoS via many ranges before v2.2.23/3.1.21/3.2.6 Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.get_byte_ranges parses the HTTP Range header without limiting the number of individual byte ranges. Although the existing fix for CVE-2024-26141 rejects ranges whose total byte coverage exceeds the file size, it does not restrict the count of ranges. An attacker can supply many small overlapping ranges such as 0-0,0-0,0-0,... to trigger disproportionate CPU, memory, I/O, and bandwidth consumption per request. This results in a denial of service condition in Rack file-serving paths that process multipart byte range responses. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.	Ubuntu Linux
CVE-2026-34786	Apr 02, 2026	Rack Static Header Bypass via URL-Encoded PATH before 2.2.23/3.1.21/3.2.6 Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static#applicable_rules evaluates several header_rules types against the raw URL-encoded PATH_INFO, while the underlying file-serving path is decoded before the file is served. As a result, a request for a URL-encoded variant of a static path can serve the same file without the headers that header_rules were intended to apply. In deployments that rely on Rack::Static to attach security-relevant response headers to static content, this can allow an attacker to bypass those headers by requesting an encoded form of the path. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.	Ubuntu Linux
CVE-2026-35386	Apr 02, 2026	OpenSSH <=10.2: Cmd Exec via Metachar Username on CLI In OpenSSH before 10.3, command execution can occur via shell metacharacters in a username within a command line. This requires a scenario where the username on the command line is untrusted, and also requires a non-default configurations of % in ssh_config.	Ubuntu Linux
CVE-2026-34785	Apr 02, 2026	Rack::Static String Prefix Disclosure in Rack <2.2.23/3.1.21/3.2.6 Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.	Ubuntu Linux
CVE-2026-34763	Apr 02, 2026	Rack::Directory Path Disclosure Pre-2.2.23, 3.1.21, 3.2.6 Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, *, or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem path in the HTML output. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.	Ubuntu Linux
CVE-2026-34831	Apr 02, 2026	Rack <2.2.23/3.1.21/3.2.6: Content-Length mismatch on multibyte 404 Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Files#fail sets the Content-Length response header using String#size instead of String#bytesize. When the response body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes actually sent on the wire. Because Rack::Files reflects the requested path in 404 responses, an attacker can trigger this mismatch by requesting a non-existent path containing percent-encoded UTF-8 characters. This results in incorrect HTTP response framing and may cause response desynchronization in deployments that rely on the incorrect Content-Length value. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.	Ubuntu Linux