Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to verify the integrity of the SAML RelayState POST parameter which allows an authenticated SAML user to join any team, including invite-only teams, via forging the team_id or invite_id fields in the RelayState.. Mattermost Advisory ID: MMSA-2026-00727
Metrics
Affected Vendors & Products
References
| Link | Providers |
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| https://mattermost.com/security-updates |
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History
Fri, 23 Oct 2026 10:30:00 +0000
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Mattermost
Mattermost mattermost |
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| Vendors & Products |
Mattermost
Mattermost mattermost |
Fri, 16 Oct 2026 15:30:00 +0000
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ssvc
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Fri, 16 Oct 2026 07:30:00 +0000
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| Description | Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to verify the integrity of the SAML RelayState POST parameter which allows an authenticated SAML user to join any team, including invite-only teams, via forging the team_id or invite_id fields in the RelayState.. Mattermost Advisory ID: MMSA-2026-00727 | |
| Title | Mattermost SAML RelayState forgery allows unauthorized team membership | |
| Weaknesses | CWE-472 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: Mattermost
Published: 2026-10-16T07:08:48.627Z
Updated: 2026-10-16T14:18:12.181Z
Reserved: 2026-07-21T10:00:44.943Z
Link: CVE-2026-16453
Updated: 2026-10-16T14:17:55.882Z
Status : Awaiting Analysis
Published: 2026-10-16T08:17:12.640
Modified: 2026-10-16T19:23:18.623
Link: CVE-2026-16453
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