Moderate severityNVD Advisory· Published Mar 26, 2026· Updated Mar 26, 2026
Guest users can view group member IDs without respecting view restrictions
CVE-2026-3115
Description
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/mattermost/mattermost/server/v8Go | >= 11.4.0, < 11.4.1 | 11.4.1 |
github.com/mattermost/mattermost/server/v8Go | >= 11.3.0-rc1, < 11.3.2 | 11.3.2 |
github.com/mattermost/mattermost/server/v8Go | >= 11.2.0-rc1, < 11.2.3 | 11.2.3 |
github.com/mattermost/mattermost/server/v8Go | >= 10.11.0-rc1, < 10.11.11 | 10.11.11 |
github.com/mattermost/mattermost/server/v8Go | >= 8.0.0-20260105080200-d27a2195068d, < 8.0.0-20260217110922-b7d4a1f1f59b | 8.0.0-20260217110922-b7d4a1f1f59b |
Affected products
1- Range: 11.2.0
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
3- github.com/advisories/GHSA-mpc7-mm28-f6wqghsaADVISORY
- mattermost.com/security-updatesghsavendor-advisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2026-3115ghsaADVISORY
News mentions
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