# CVE-2025-12756: GO-2025-4172 - Mattermost fails to validate user permissions when deleting comments in Boards in github.com/mattermost/mattermost

Source: https://junglewise.ai/threats/cve-2025-12756-mattermost-fails-to-validate-user-permissions-when-deleting  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-12-01  
License: CC BY 4.0 with a link back

CVE-2025-12756 · Severity: medium · CVSS 4.3 · Published 2025-12-01

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.

Technologies: [github.com/mattermost/mattermost (Go)](https://junglewise.ai/threats/technologies/github-com-mattermost-mattermost), [github.com/mattermost/mattermost-server (Go)](https://junglewise.ai/threats/technologies/github-com-mattermost-mattermost-server), [github.com/mattermost/mattermost-server/v5 (Go)](https://junglewise.ai/threats/technologies/github-com-mattermost-mattermost-server-v5), [github.com/mattermost/mattermost-server/v6 (Go)](https://junglewise.ai/threats/technologies/github-com-mattermost-mattermost-server-v6), [github.com/mattermost/mattermost/server/v8 (Go)](https://junglewise.ai/threats/technologies/github-com-mattermost-mattermost-server-v8), [Mattermost Server](https://junglewise.ai/threats/technologies/server-public). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Mattermost](https://junglewise.ai/threats/vendors/mattermost).

## Quick answers

**Is CVE-2025-12756 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-12756 being exploited in the wild.

**How severe is CVE-2025-12756?** Medium severity, with a CVSS score of 4.3, published 1 December 2025.

**Which products and versions are affected?** github.com/mattermost/mattermost (Go) SEMVER:introduced=0, SEMVER:introduced=10.11.0,last_affected=10.11.4; github.com/mattermost/mattermost-server (Go) SEMVER:introduced=0; github.com/mattermost/mattermost-server/v5 (Go) SEMVER:introduced=0; github.com/mattermost/mattermost-server/v6 (Go) SEMVER:introduced=0; and 1 more.

**Is there a fix for CVE-2025-12756?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2025-12756?** Check whether you run github.com/mattermost/mattermost (Go), github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server/v5 (Go) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- github.com/mattermost/mattermost (Go) SEMVER:introduced=0, SEMVER:introduced=10.11.0,last_affected=10.11.4
- github.com/mattermost/mattermost-server (Go) SEMVER:introduced=0
- github.com/mattermost/mattermost-server/v5 (Go) SEMVER:introduced=0
- github.com/mattermost/mattermost-server/v6 (Go) SEMVER:introduced=0
- github.com/mattermost/mattermost/server/v8 (Go) SEMVER:introduced=0, SEMVER:introduced=0,last_affected=8.0.0-20251013062617-7977e7e6dae3
- Mattermost Server

## Identifiers

- CVE-2025-12756
- GHSA-p6gj-jc38-x2m7
- GO-2025-4172

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