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rsync EUVDEUVD-2026-58039

| CVE-2026-53801 HIGH
Improper Link Resolution Before File Access (CWE-59)
2026-08-13 VulnCheck
8.2
CVSS 4.0 · Vendor: VulnCheck
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Severity by source

Vendor (VulnCheck) PRIMARY
8.2 HIGH
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vuln.today AI
5.3 MEDIUM

Creating or renaming symlinks in the scanned path requires write access, indicating at minimum low-privileged filesystem access (PR:L); AC:H reflects the race condition timing constraint.

3.1 AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0 AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
SUSE
6.5 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Red Hat
5.9 MEDIUM
qualitative

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
X

Lifecycle Timeline

3
Source Code Evidence Fetched
Aug 13, 2026 - 15:52 vuln.today
Analysis Generated
Aug 13, 2026 - 15:52 vuln.today
CVE Published
Aug 13, 2026 - 14:41 cve.org
HIGH 8.2

DescriptionCVE.org

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.

AnalysisAI

Symlink race condition in rsync before 3.5.0 allows directory traversal beyond the configured module root during sender-side scanning. Attackers with write access to a path component of the scanned tree can exploit a TOCTOU window between lstat() and opendir() system calls to redirect traversal outside the module boundary, causing rsync to enumerate and transfer files from unintended filesystem locations. This affects both daemon-mode and non-daemon sender-side scanning configurations; no public exploit has been identified at time of analysis, and the vulnerability is not listed in CISA KEV.

Technical ContextAI

The vulnerability is classified under CWE-59 (Improper Link Resolution Before File Access), specifically a time-of-check to time-of-use (TOCTOU) race condition in rsync's sender directory scanning logic. When rsync scans a directory tree, it calls lstat() on a path entry to inspect its type, then subsequently calls opendir() to descend into it. An attacker who atomically replaces a symlink with a real directory entry pointing outside the module root between these two kernel calls causes rsync to accept the new directory as in-scope and traverse it. The affected product scope is cpe:2.3:a:rsyncproject:rsync:*:*:*:*:*:*:*:* - all releases prior to 3.5.0 - and the flaw is present regardless of whether rsync operates in daemon mode (with defined module roots) or in direct non-daemon sender mode.

RemediationAI

Upgrade rsync to version 3.5.0 or later, confirmed as the patching release by the GitHub release page at https://github.com/RsyncProject/rsync/releases/tag/v3.5.0 and the vendor security advisory GHSA-mch3-qr4p-chgm at https://github.com/RsyncProject/rsync/security/advisories/GHSA-mch3-qr4p-chgm. If immediate upgrade is not feasible, restrict write access to all rsync daemon module paths so untrusted users cannot create or manipulate symlinks within the scanned tree - this directly removes the prerequisite for exploitation but may require reconfiguring legitimate upload workflows. Ensure daemon-mode rsync modules are configured with 'use chroot = yes' (the default on systems with chroot capability) to limit the blast radius of traversal; note that chroot requires rsync to run with elevated privileges initially and may break setups relying on relative paths. Additionally, restricting module access via 'hosts allow' in rsyncd.conf reduces the attacker population. The 'follow symlinks = no' option does not fully mitigate this flaw since the race occurs before symlink-following logic, so it should not be relied upon as a standalone control.

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS Affected
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS Affected
SUSE Linux Enterprise Micro 5.3 Affected

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EUVD-2026-58039 vulnerability details – vuln.today

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