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Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate that the RefreshedToken differs from the original invite token during remote cluster invite confirmation which allows an authenticated attacker to bypass token rotation and reuse the original invite token via sending a crafted invite confirmation with a RefreshedToken matching the original token. Mattermost Advisory ID: MMSA-2026-00575

PUBLISHED Reserved 2026-03-16 | Published 2026-05-18 | Updated 2026-05-18 | Assigner Mattermost




LOW: 3.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Problem types

CWE-863: Incorrect Authorization

Product status

Default status
unaffected

11.5.0 (semver)
affected

10.11.0 (semver)
affected

11.6.0
unaffected

11.5.2
unaffected

10.11.14
unaffected

Credits

daw10 finder

References

mattermost.com/security-updates (MMSA-2026-00575) vendor-advisory

cve.org (CVE-2026-4273)

nvd.nist.gov (CVE-2026-4273)

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