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 restrict Slack import account binding to system administrator-initiated imports which allows an authenticated attacker with team admin privileges to force-add existing Mattermost users to their team and forge posts attributed to those users' identities via a crafted Slack export containing target users' email addresses.. Mattermost Advisory ID: MMSA-2026-00757
Metrics
Affected Vendors & Products
References
| Link | Providers |
|---|---|
| https://mattermost.com/security-updates |
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History
Sat, 17 Oct 2026 16:45:00 +0000
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Mattermost
Mattermost mattermost |
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| Vendors & Products |
Mattermost
Mattermost mattermost |
Fri, 16 Oct 2026 12:30:00 +0000
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| Metrics |
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 restrict Slack import account binding to system administrator-initiated imports which allows an authenticated attacker with team admin privileges to force-add existing Mattermost users to their team and forge posts attributed to those users' identities via a crafted Slack export containing target users' email addresses.. Mattermost Advisory ID: MMSA-2026-00757 | |
| Title | Mattermost Server fails to restrict Slack import account binding, allowing team admins to forge posts as existing users | |
| Weaknesses | CWE-862 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: Mattermost
Published: 2026-10-16T07:16:19.062Z
Updated: 2026-10-16T11:28:45.200Z
Reserved: 2026-08-04T10:05:23.880Z
Link: CVE-2026-18799
Updated: 2026-10-16T11:28:40.139Z
Status : Awaiting Analysis
Published: 2026-10-16T08:17:13.073
Modified: 2026-10-16T19:23:18.623
Link: CVE-2026-18799
No data.