CVE-2026-53786: CWE-863 Incorrect Authorization in RsyncProject rsync
CVE-2026-53786 is a medium severity vulnerability in rsync before version 3.5.0 that allows authenticated clients to bypass module-level filter restrictions. By supplying malicious --filter merge file directives, attackers can override intended file access restrictions and gain access to files excluded by the module filter.
AI Analysis
Technical Summary
The vulnerability in RsyncProject's rsync (CVE-2026-53786) involves an incorrect authorization flaw (CWE-863) where authenticated clients can inject client-side merge file directives during filter evaluation. This injection allows attackers to supersede daemon module-level filter restrictions by supplying malicious --filter merge file directives, effectively bypassing intended access controls and gaining unauthorized access to files that should be excluded by the module filter. This affects rsync versions up to and including 3.4.4.
Potential Impact
Authenticated attackers can bypass module-level filter restrictions and access files that the rsync daemon module filter was designed to exclude. This could lead to unauthorized disclosure of sensitive files. The CVSS 4.0 base score is 6.9 (medium severity), indicating a significant but not critical impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch link is provided, users should monitor for updates from RsyncProject and apply any official patches once available. Until then, restrict authenticated client access and review filter configurations to minimize exposure.
CVE-2026-53786: CWE-863 Incorrect Authorization in RsyncProject rsync
Description
CVE-2026-53786 is a medium severity vulnerability in rsync before version 3.5.0 that allows authenticated clients to bypass module-level filter restrictions. By supplying malicious --filter merge file directives, attackers can override intended file access restrictions and gain access to files excluded by the module filter.
CVSS v4.0
Score 6.9medium
Affected software
RsyncProject
rsync
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in RsyncProject's rsync (CVE-2026-53786) involves an incorrect authorization flaw (CWE-863) where authenticated clients can inject client-side merge file directives during filter evaluation. This injection allows attackers to supersede daemon module-level filter restrictions by supplying malicious --filter merge file directives, effectively bypassing intended access controls and gaining unauthorized access to files that should be excluded by the module filter. This affects rsync versions up to and including 3.4.4.
Potential Impact
Authenticated attackers can bypass module-level filter restrictions and access files that the rsync daemon module filter was designed to exclude. This could lead to unauthorized disclosure of sensitive files. The CVSS 4.0 base score is 6.9 (medium severity), indicating a significant but not critical impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch link is provided, users should monitor for updates from RsyncProject and apply any official patches once available. Until then, restrict authenticated client access and review filter configurations to minimize exposure.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-06-10T20:14:32.827Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a7ddec4bf8831d5395cfc83
Added to database: 08/13/2026, 15:12:04 UTC
Last enriched: 08/21/2026, 13:25:09 UTC
Last updated: 09/26/2026, 01:47:42 UTC
Views: 37
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