Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels by pre-registering a user account with a predictable plugin bot username.. Mattermost Advisory ID: MMSA-2026-00649
Metrics
Affected Vendors & Products
References
| Link | Providers |
|---|---|
| https://mattermost.com/security-updates |
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History
Fri, 12 Jun 2026 18:45:00 +0000
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| First Time appeared |
Mattermost
Mattermost mattermost |
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| Vendors & Products |
Mattermost
Mattermost mattermost |
Fri, 12 Jun 2026 18:30:00 +0000
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ssvc
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Fri, 12 Jun 2026 17:15:00 +0000
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| Description | Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels by pre-registering a user account with a predictable plugin bot username.. Mattermost Advisory ID: MMSA-2026-00649 | |
| Title | Plugin bot username conflict allows user account to be used as bot identity in Mattermost Server | |
| Weaknesses | CWE-200 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: Mattermost
Published:
Updated: 2026-06-12T17:18:30.553Z
Reserved: 2026-04-09T19:20:26.868Z
Link: CVE-2026-6046
Updated: 2026-06-12T17:18:27.704Z
Status : Received
Published: 2026-06-12T17:16:26.957
Modified: 2026-06-12T17:16:26.957
Link: CVE-2026-6046
No data.
OpenCVE Enrichment
Updated: 2026-06-12T18:30:31Z