Mattermost fails to validate user permissions when deleting comments in Boards
CVE-2025-12756GHSA-p6gj-jc38-x2m7
What to do
Vendor response not established. Follow the primary source's mitigation guidance and check back for a fix.
This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.
Affected packages
Go github.com/mattermost/mattermost/server/v8
- Affected
- <= 8.0.0-20251013062617-7977e7e6dae3
- Fixed in
- no fixed version recorded
Go github.com/mattermost/mattermost
- Affected
- >= 10.11.0, <= 10.11.4>= 10.12.0, <= 10.12.1>= 10.5.0, <= 10.5.12>= 11.0.0, <= 11.0.2
- Fixed in
- no fixed version recorded
Sources
- GitHub Advisory Database and maintainer security advisories on GitHub
GitHub-reviewed advisory GHSA-p6gj-jc38-x2m7 lists affected ranges: Go github.com/mattermost/mattermost/server/v8 >=0 =10.11.0 =10.12.0 =10.5.0 =11.0.0 <=11.0.2
VerifiedObserved Structured GitHub Advisory Database record (type=reviewed) from the GitHub REST API.
Severity and exploitation
- Exploitation
- No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
- CVSS
- 4.3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- EPSS
- CVE-2025-12756: 0.20% estimated exploitation activity in the next 30 days; percentile 9.33 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description
As published by the source; long descriptions are shortened.
Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to validate user permissions when deleting comments in Boards, which allows an authenticated user with the editor role to delete comments created by other users.
Dates and revisions
- Published by the source
- Last modified by the source
- Source last checked
- Revision 1 · created ·
Published from ghsa record GHSA-p6gj-jc38-x2m7
Agent brief
Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.
# Patch Next advisory brief: CVE-2025-12756 Advisory: Mattermost fails to validate user permissions when deleting comments in Boards IDs: CVE-2025-12756, GHSA-p6gj-jc38-x2m7 Record: https://patchnext.com/advisories/cve-2025-12756 (revision 1, source checked 26 Oct 2026, 15:13 UTC) Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected. Severity: Medium (CVSS 4.3) Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV. Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed. ## Affected components - Go github.com/mattermost/mattermost/server/v8: affected <= 8.0.0-20251013062617-7977e7e6dae3 - Go github.com/mattermost/mattermost: affected >= 10.11.0, <= 10.11.4; >= 10.12.0, <= 10.12.1; >= 10.5.0, <= 10.5.12; >= 11.0.0, <= 11.0.2 ## Suggested inspection (read-only) - Go github.com/mattermost/mattermost/server/v8: check the installed version with your package manager. - Go github.com/mattermost/mattermost: check the installed version with your package manager. ## Supported action No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything. ## Required regression checks - Run the test suite and a production build. - Exercise the features that depend on github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost. - Repeat the inspection and confirm that only fixed versions remain installed. ## Rollback considerations - Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward. ## Unresolved questions - Which deployments run an affected version? - Exploitation status can change. Check again before lowering the priority. - Mark the work resolved only after the fixed version is verified in production. ## Sources - Verified: https://github.com/advisories/GHSA-p6gj-jc38-x2m7 (GitHub-reviewed advisory GHSA-p6gj-jc38-x2m7 lists affected ranges: Go github.com/mattermost/mattermost/server/v8 >=0 =10.11.0 =10.12.0 =10.5.0 =11.0.0 <=11.0.2) Commands are suggestions: review each one before running it.
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