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Description

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

PUBLISHED Reserved 2026-04-24 | Published 2026-06-12 | Updated 2026-06-12 | Assigner Mattermost




HIGH: 7.6CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:L

Problem types

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Product status

Default status
unaffected

11.6.0 (semver)
affected

11.5.0 (semver)
affected

10.11.0 (semver)
affected

10.11.0 (semver)
affected

11.7.0
unaffected

11.6.2
unaffected

11.5.5
unaffected

10.11.16
unaffected

10.11.17
unaffected

Credits

Hassan Mohammed finder

References

mattermost.com/security-updates (MMSA-2026-00661) vendor-advisory

cve.org (CVE-2026-6961)

nvd.nist.gov (CVE-2026-6961)

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