CVE-2026-6957

4.9 mediumEPSS 0.3%

Medium (4.9) in mattermost legal hold. EPSS 0.3% chance of exploitation in the next 30 days.

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

Severity

CVSS 3.1

4.9 medium

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 22% of CVEs (scores of 2026-10-31)
CWE: CWE-22
Published: 2026-05-27
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mattermost:legal_hold

References

https://mattermost.com/security-updates

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