Samba Rsync

Rsync <=3.4.3 TOCTOU Race Allows Arbitrary File Write/Privilege Escalation
CVE-2026-29518 7.8 - High - May 20, 2026

Rsync versions before 3.4.3 contain a time-of-check to time-of-use (TOCTOU) race condition in daemon file handling that allows attackers to redirect file writes outside intended directories by replacing parent directory components with symbolic links. Attackers with write access to a module path can exploit this race condition to create or overwrite arbitrary files, potentially modifying sensitive system files and achieving privilege escalation when the daemon runs with elevated privileges. This vulnerability can only be triggered if the chroot setting is false.

TOCTTOU

Rsync Hostname-based ACL bypass <3.4.3: Auth bypass via PTR
CVE-2026-43617 4.8 - Medium - May 20, 2026

Rsync version 3.4.2 and prior contain an authorization bypass vulnerability in the rsync daemon's hostname-based access control list enforcement when configured with chroot. Attackers can bypass hostname-based deny rules by controlling the PTR record for their source IP address, allowing connections from hostnames that administrators intended to deny when reverse DNS resolution fails and defaults to UNKNOWN.

Authentication Bypass by Alternate Name

Rsync 3.4.2 and earlier Integer Overflow in compressed-token decoder
CVE-2026-43618 8.1 - High - May 20, 2026

Rsync version 3.4.2 and prior contain an integer overflow vulnerability in the compressed-token decoder where a 32-bit signed counter is not checked for overflow, allowing a malicious sender to trigger an overflow that causes the receiver process to read and return data from outside the intended buffer bounds. Attackers can exploit this vulnerability to disclose process memory contents including environment variables, passwords, heap and stack data, and library memory pointers, significantly reducing ASLR effectiveness and facilitating further exploitation.

Integer Overflow or Wraparound

rsync 3.4.2 and earlier Symlink Race Condition in Path-based Syscalls
CVE-2026-43619 6.3 - Medium - May 20, 2026

Rsync version 3.4.2 and prior contain symlink race condition vulnerabilities in path-based system calls including chmod, lchown, utimes, rename, unlink, mkdir, symlink, mknod, link, rmdir, and lstat that allow local attackers to redirect operations to files outside the exported rsync module. Attackers with local filesystem access can exploit the timing window between path resolution and syscall execution by swapping symlinks to apply sender-supplied permissions, ownership, timestamps, or filenames to arbitrary files outside the intended module boundary on rsync daemons configured with 'use chroot = no'.

TOCTTOU

Rsync <3.4.3: Receiver-side OOB array read crash via CF_INC_RECURSE
CVE-2026-43620 6.5 - Medium - May 20, 2026

Rsync version 3.4.2 and prior contain a receiver-side out-of-bounds array read vulnerability in recv_files() in receiver.c that allows a malicious rsync server to crash the rsync client process. Attackers can exploit the vulnerability by setting CF_INC_RECURSE in compatibility flags and sending a specially crafted file list where the first sorted entry is not the leading dot directory, followed by a transfer record with ndx=0 and an iflag word without ITEM_TRANSFER, causing the receiver to read 8 bytes before the allocated pointer array and dereference an invalid pointer at an unmapped address, resulting in a deterministic SIGSEGV crash of the rsync client.

Out-of-bounds Read

Rsync <3.4.3: OOB stack write in establish_proxy_connection()
CVE-2026-45232 3.1 - Low - May 20, 2026

Rsync versions before 3.4.3 contain an off-by-one out-of-bounds stack write vulnerability in the establish_proxy_connection() function in socket.c that allows network attackers to corrupt stack memory by sending a malformed HTTP proxy response. Attackers can exploit this by positioning themselves between the client and proxy or controlling the proxy server to send a response line of 1023 or more bytes without a newline terminator, causing a null byte to be written to an out-of-bounds stack address when the RSYNC_PROXY environment variable is set.

off-by-five

rsync 3.0.13.4.1 Receiver UAF in receive_xattr (qsort untrusted len)
CVE-2026-41035 7.4 - High - April 16, 2026

In rsync 3.0.1 through 3.4.1, receive_xattr relies on an untrusted length value during a qsort call, leading to a receiver use-after-free. The victim must run rsync with -X (aka --xattrs). On Linux, many (but not all) common configurations are vulnerable. Non-Linux platforms are more widely vulnerable.

length manipulation

rsync Daemon Heap Bof via Checksum Length Overrun
CVE-2024-12084 9.8 - Critical - January 15, 2025

A heap-based buffer overflow flaw was found in the rsync daemon. This issue is due to improper handling of attacker-controlled checksum lengths (s2length) in the code. When MAX_DIGEST_LEN exceeds the fixed SUM_LENGTH (16 bytes), an attacker can write out of bounds in the sum2 buffer.

Heap-based Buffer Overflow

Rsync Server Remote File Enumeration via Checksum Exploit
CVE-2024-12086 6.1 - Medium - January 14, 2025

A flaw was found in rsync. It could allow a server to enumerate the contents of an arbitrary file from the client's machine. This issue occurs when files are being copied from a client to a server. During this process, the rsync server will send checksums of local data to the client to compare with in order to determine what data needs to be sent to the server. By sending specially constructed checksum values for arbitrary files, an attacker may be able to reconstruct the data of those files byte-by-byte based on the responses from the client.

Detection of Error Condition Without Action

Rsync: Checksum Length Manipulation Enables Stack Data Leak
CVE-2024-12085 7.5 - High - January 14, 2025

A flaw was found in rsync which could be triggered when rsync compares file checksums. This flaw allows an attacker to manipulate the checksum length (s2length) to cause a comparison between a checksum and uninitialized memory and leak one byte of uninitialized stack data at a time.

Use of Uninitialized Resource

Path traversal in rsync via --inc-recursive option
CVE-2024-12087 6.5 - Medium - January 14, 2025

A path traversal vulnerability exists in rsync. It stems from behavior enabled by the `--inc-recursive` option, a default-enabled option for many client options and can be enabled by the server even if not explicitly enabled by the client. When using the `--inc-recursive` option, a lack of proper symlink verification coupled with deduplication checks occurring on a per-file-list basis could allow a server to write files outside of the client's intended destination directory. A malicious server could write malicious files to arbitrary locations named after valid directories/paths on the client.

Directory traversal

Rsync --safe-links Path Traversal, Arbitrary File Write
CVE-2024-12088 6.5 - Medium - January 14, 2025

A flaw was found in rsync. When using the `--safe-links` option, the rsync client fails to properly verify if a symbolic link destination sent from the server contains another symbolic link within it. This results in a path traversal vulnerability, which may lead to arbitrary file write outside the desired directory.

Directory traversal

Rsync <3.2.5 Remote File Overwrite via Client Name Validation Bypass
CVE-2022-29154 7.4 - High - August 02, 2022

An issue was discovered in rsync before 3.2.5 that allows malicious remote servers to write arbitrary files inside the directories of connecting peers. The server chooses which files/directories are sent to the client. However, the rsync client performs insufficient validation of file names. A malicious rsync server (or Man-in-The-Middle attacker) can overwrite arbitrary files in the rsync client target directory and subdirectories (for example, overwrite the .ssh/authorized_keys file).

Improper Input Validation

A flaw was found in rsync in versions since 3.2.0pre1
CVE-2020-14387 7.4 - High - May 27, 2021

A flaw was found in rsync in versions since 3.2.0pre1. Rsync improperly validates certificate with host mismatch vulnerability. A remote, unauthenticated attacker could exploit the flaw by performing a man-in-the-middle attack using a valid certificate for another hostname which could compromise confidentiality and integrity of data transmitted using rsync-ssl. The highest threat from this vulnerability is to data confidentiality and integrity. This flaw affects rsync versions before 3.2.4.

Improper Validation of Certificate with Host Mismatch

The parse_arguments function in options.c in rsyncd in rsync before 3.1.3 does not prevent multiple --protect-args uses, which
CVE-2018-5764 7.5 - High - January 17, 2018

The parse_arguments function in options.c in rsyncd in rsync before 3.1.3 does not prevent multiple --protect-args uses, which allows remote attackers to bypass an argument-sanitization protection mechanism.

rsync 3.1.1 allows remote attackers to write to arbitrary files
CVE-2014-9512 - February 12, 2015

rsync 3.1.1 allows remote attackers to write to arbitrary files via a symlink attack on a file in the synchronization path.

insecure temporary file

rsync 3.x before 3.0.8, when certain recursion, deletion, and ownership options are used
CVE-2011-1097 - March 30, 2011

rsync 3.x before 3.0.8, when certain recursion, deletion, and ownership options are used, allows remote rsync servers to cause a denial of service (heap memory corruption and application crash) or possibly execute arbitrary code via malformed data.

Buffer Overflow

Buffer overflow in rsync 2.6.9 to 3.0.1, with extended attribute (xattr) support enabled, might
CVE-2008-1720 - April 10, 2008

Buffer overflow in rsync 2.6.9 to 3.0.1, with extended attribute (xattr) support enabled, might allow remote attackers to execute arbitrary code via unknown vectors.