Auth bypass in Rsyncproject Rsync
CVE-2026-53786
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (31.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 31.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Rsyncproject Rsync — versions 0, 3.5.0
- Samba Rsync
Weakness classification (CWE)
References
- github.com/RsyncProject/rsync/releases/tag/v3.5.0 (release-notes, Product, Release Notes)
- github.com/RsyncProject/rsync/security/advisories/GHSA-mrc3-6cwx-hch6 (vendor-advisory, Vendor Advisory)
- www.vulncheck.com/advisories/rsync-filter-rule-bypass-via-filter-merge-directive (Third Party Advisory, Release Notes, third-party-advisory)
Frequently asked questions
- What is CVE-2026-53786?
- CVE-2026-53786 is a medium-severity vulnerability in Rsyncproject Rsync, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-08-13.
- How severe is CVE-2026-53786?
- Medium severity. CVSS v3 base score is 6.5 out of 10.