What’s Vulnerable › Vulnerabilities
CVE-2026-6957: Path traversal in Mattermost Legal Hold plugin via unsanitized file name from federated peer allows arbitrary file write.
- Severity: medium (CVSS 4.9 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-05-27 · updated 2026-06-17
- Weakness: CWE-22
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: through 1.1.5
References
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