Description
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
Affected products
mattermost: legal hold
References1
- mattermost.com/security-updates Vendor Advisory
Metrics
- CVSS 3.1
-
4.9
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N - EPSS — exploit probability
- 0% percentile: 23 · as of 14 November 2026
- CWE
- CWE-22
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