rsync 3.4.2 < 3.5.0 DoS via --zt Zstandard Compression Thread Exhaustion

rsync 3.2.3 < 3.5.0 Out-of-Bounds Write via parsesizearg()

rsync 3.0.0 < 3.5.0 Daemon Crash via Malformed File List Entry

rsync 3.2.5 < 3.5.0 Heap Out-of-Bounds Write via files-from Entry

rsync 3.1.0 before 3.5.0 contains an authorization bypass in auth users directive parsing. The auth users parser uses comma-only tokenization when splitting the user list, which fails to correctly handle entries of the form @Group Name where the group name contains a space. The space within the group name causes the parser to split the entry at the space boundary, discarding the deny rule associated with the group. An authenticated user whose username or group membership would be denied by an @Group Name auth users entry can connect to a restricted module because the deny rule is silently discarded during parsing.

rsync before 3.5.0 contains a symlink race condition vulnerability in the sender's directory scanning logic that allows attackers to cause the sender to enumerate and transfer files outside the module root's intended subtree. Attackers who can create or manipulate symlinks in a path component of the scanned tree can replace a symlink with a directory entry pointing outside the module root between the lstat() call and the subsequent opendir() call, exposing files beyond the intended root in both daemon-mode and non-daemon sender-side scanning.

rsync before 3.5.0 contains a symlink race condition vulnerability in the --remove-source-files feature that allows attackers with symlink creation access to cause arbitrary file deletion. Attackers can atomically substitute a symlink for a source file between transfer completion and the unlink() call, causing rsync to delete the symlink target rather than the intended source file.

rsync before 3.5.0 contains a symlink race condition vulnerability that allows local attackers to cause rsync to apply arbitrary ACLs or extended attributes to unintended files by substituting a symlink at a predictable destination path between the file write and the subsequent aclsetfile() or lsetxattr() call. Attackers can exploit this timing window to redirect ACL and xattr application through a crafted symlink to files outside the intended destination tree, potentially granting elevated permissions and enabling local privilege escalation.

rsync before 3.5.0 contains a symlink race condition vulnerability in the sender's source tree traversal that allows an attacker who can manipulate a parent directory of the source tree to redirect file reads to unintended paths. Attackers can atomically replace a parent directory component with a symlink pointing outside the source root between path resolution and file open operations to disclose file contents outside the intended transfer root.

rsync before 3.5.0 contains an arbitrary file write vulnerability that allows attackers to write files outside the intended destination tree by specifying an absolute path via --temp-dir or --link-dest options. The rename-confinement logic is bypassed when these options resolve to paths outside the destination tree, enabling attacker-controlled values to write files to arbitrary locations accessible to the rsync process.

rsync daemon before 3.5.0 contains an IP address spoofing vulnerability that allows unauthenticated remote attackers to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source address. Attackers who can connect directly to the rsync daemon can inject a spoofed source IP in the PROXY protocol header to circumvent hosts allow/deny rules, gaining unauthorized access that would otherwise be blocked based on their real source address.

rsync before 3.5.0 contains an improper path handling vulnerability that allows a malicious sender to expand the scope of --delete operations beyond the intended destination subtree by sending a crafted file list that causes rsync to reclassify implied parent directory entries or treat synthetic paths as the transfer root. Attackers can exploit multiple variants including implied parent reclassification, synthetic root path construction, legacy protocol behavior below version 30, and non-directory root handling to cause the receiver to delete files outside the authorized destination directory.

rsync before 3.5.0 contains a privilege confusion vulnerability in the name-converter subprocess uid/gid mapping that allows local attackers to cause transferred files to be owned by root by influencing name-converter responses to return empty values. When the name-converter subprocess returns an empty response for a uid or gid lookup, rsync incorrectly interprets it as a successful resolution to uid/gid 0 (root) rather than a lookup failure, and if the name-converter also signals fake super-user status, rsync proceeds with root ownership assignments for transferred files.

rsync before 3.5.0 contains a filter rule bypass vulnerability that allows authenticated clients to override module-level filter restrictions by supplying malicious --filter merge file directives. Attackers can inject client-side merge file directives during filter evaluation to introduce rules that supersede daemon module-level restrictions, gaining access to files the module filter was intended to exclude.

rsync before 3.5.0 contains a path traversal vulnerability that allows remote clients to access files outside the intended module root when use chroot is disabled and the module root path or a component of it is a symlink. The daemon calls chdir() to the module root at session initialization without resolving symlinks via realpath() or equivalent, causing subsequent relative-path operations to reference files relative to the symlink target rather than the intended module root, enabling unauthorized file access.

rsync before 3.5.0 contains a symlink following vulnerability that allows local attackers to overwrite arbitrary files by placing a symlink at a predictable output path such as --log-file, --write-batch, or daemon-mode log and statistics paths. Attackers can exploit rsync's failure to reject symlinks during ancillary file writes to redirect output to arbitrary filesystem locations, achieving local privilege escalation on installations where rsync runs with elevated privileges such as setuid or privileged daemon configurations.

rsync before 3.5.0 contains an arbitrary file read vulnerability that allows attackers to read files accessible to the rsync daemon process by exploiting symlink following in input configuration file handling including --files-from, --password-file, and filter merge files. Attackers can place a symlink at a predictable --files-from or --password-file path, or supply a --files-from path that escapes the daemon module root, to read arbitrary files accessible to the rsync process.

Last updated 2 June 2026

Last updated 2 June 2026

Last updated 2 June 2026

Last updated 22 May 2026

A flaw was found in rsync. An rsync daemon configured with "use chroot = no" is exposed to a time-of-check / time-of-use race on parent path components. A local attacker with write access to a module can replace a parent directory component with a symlink between the receiver's check and its open(), redirecting reads (basis-file disclosure) and writes (file overwrite) outside the module. Under elevated daemon privilege this allows privilege escalation. Default "use chroot = yes" is not exposed.

A flaw was found in rsync. An authenticated daemon peer can exploit an integer overflow vulnerability in the compressed-token decoder. By carefully manipulating the compressed-token, a malicious sender can trigger an overflow, leading to remote memory disclosure. This allows an attacker to leak sensitive process memory contents, including environment variables, passwords, and memory pointers, which significantly weakens Address Space Layout Randomization (ASLR) and can facilitate further exploitation.

In rsync 3.0.1 through 3.4.1, receivexattr 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.

This vulnerability stems from a race condition in rsync's handling of symbolic links. By exploiting timing differences, an attacker can bypass the expected behavior of skipping symbolic links during file synchronization. This flaw becomes critical in scenarios where rsync runs with elevated privileges, as it can inadvertently expose sensitive files to unprivileged users, potentially leading to privilege escalation.

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

rsync --safe-links options fail to verify whether a symbolic link destination contains another symbolic link with it leading to a path traversal vulnerability

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.

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.

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.