Mattermost <=11.6.1/11.5.4 Path Traversal via FILEINFO.Name
CVE-2026-6961 Published on June 12, 2026
CVE-2026-6961: Path traversal via unsanitized FileInfo.Name in Mattermost federation sync
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field.. Mattermost Advisory ID: MMSA-2026-00661
Vulnerability Analysis
CVE-2026-6961 can be exploited with network access, and requires user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, a high impact on integrity, and a small impact on availability.
Weakness Type
What is a Directory traversal Vulnerability?
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
CVE-2026-6961 has been classified to as a Directory traversal vulnerability or weakness.
Products Associated with CVE-2026-6961
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Affected Versions
Mattermost:- Version 11.6.0, <= 11.6.1 is affected.
- Version 11.5.0, <= 11.5.4 is affected.
- Version 10.11.0, <= 10.11.15 is affected.
- Version 10.11.0, <= 10.11.16 is affected.
- Version 11.7.0 is unaffected.
- Version 11.6.2 is unaffected.
- Version 11.5.5 is unaffected.
- Version 10.11.16 is unaffected.
- Version 10.11.17 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.