CVE-2026-53786: rsync < 3.5.0 Filter Rule Bypass via --filter Merge Directive
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
rsyncto a version that resolves this vulnerability.Fixed in 3.5.0
Event History
Frequently Asked Questions
What is the severity of CVE-2026-53786?
The severity of CVE-2026-53786 is medium with a CVSS score of 6.5.
How do I fix CVE-2026-53786?
To fix CVE-2026-53786, upgrade to rsync version 3.5.0 or later.
What type of vulnerability is CVE-2026-53786?
CVE-2026-53786 is a filter rule bypass vulnerability in rsync.
Who is affected by CVE-2026-53786?
Authenticated clients using rsync versions prior to 3.5.0 are affected by CVE-2026-53786.
What can attackers achieve with CVE-2026-53786?
Attackers can override module-level filter restrictions and potentially execute unauthorized file transfer rules.