CVE-2026-6957

Mattermost Plugins versions <=1.1.5 fail to sanitize filenames received from federated peers before using them to construct export destination paths, which allows an administrator of a remote federated Mattermost server to write files to arbitrary locations within the target server's filestore via a malicious filename delivered through the shared-channel attachment sync protocol. Mattermost Advisory ID: MMSA-2026-00659

Score
CVSS 3.1 8.0 High
Status
Analyzed - responsibledisclosure@mattermost.com
Published
2026-05-27
Last modified
2026-05-28
Weaknesses
CWE-22

Affected products

References

 
 
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