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Description

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4 fail to verify whether a guest account is deactivated before creating a session in the magic-link token login path, which allows a deactivated guest user to obtain a fully functional session via a magic-link token issued prior to deactivation.. Mattermost Advisory ID: MMSA-2026-00681

PUBLISHED Reserved 2026-05-26 | Published 2026-07-13 | Updated 2026-07-13 | 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-305 – Authentication Bypass by Primary Weakness

Product status

Default status
unaffected

11.7.0 (semver)
affected

11.6.0 (semver)
affected

11.8.0
unaffected

11.7.3
unaffected

11.6.5
unaffected

Credits

alimursaliyev finder

References

mattermost.com/security-updates (MMSA-2026-00681) vendor-advisory

cve.org (CVE-2026-9597)

nvd.nist.gov (CVE-2026-9597)

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