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Description

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548

PUBLISHED Reserved 2026-01-15 | Published 2026-02-16 | Updated 2026-02-17 | Assigner Mattermost




MEDIUM: 5.4CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Problem types

CWE-303: Incorrect Implementation of Authentication Algorithm

Product status

Default status
unaffected

11.1.0 (semver)
affected

10.11.0 (semver)
affected

11.2.0 (semver)
affected

11.3.0
unaffected

11.1.3
unaffected

10.11.10
unaffected

11.2.2
unaffected

Credits

daw10 finder

References

mattermost.com/security-updates (MMSA-2025-00548) vendor-advisory

cve.org (CVE-2026-0999)

nvd.nist.gov (CVE-2026-0999)

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