# CVE-2025-11777: GO-2025-4122 - Mattermost Incorrect Authorization vulnerability in github.com/mattermost/mattermost Source: https://junglewise.ai/threats/cve-2025-11777-mattermost-incorrect-authorization-vulnerability Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats Published: 2025-11-13 License: CC BY 4.0 with a link back CVE-2025-11777 · Severity: low · CVSS 3.1 · Published 2025-11-13 Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata and channel membership information from other teams via the API endpoint 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-2025-11777 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-11777 being exploited in the wild. **How severe is CVE-2025-11777?** Low severity, with a CVSS score of 3.1, published 13 November 2025. **Which products and versions are affected?** github.com/mattermost/mattermost (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250905150616-ba86dfc5876b; github.com/mattermost/mattermost-server (Go) SEMVER:introduced=10.11.0,fixed=10.11.4, SEMVER:introduced=10.5.0+incompatible,fixed=10.5.12+incompatible,introduced=10.11.0+incompatible,fixed=10.11.4+incompatible; github.com/mattermost/mattermost-server/v5 (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250905150616-ba86dfc5876b; github.com/mattermost/mattermost-server/v6 (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250905150616-ba86dfc5876b; and 2 more. **Is there a fix for CVE-2025-11777?** Yes. github.com/mattermost/mattermost (Go): upgrade to 5.3.2-0.20250905150616-ba86dfc5876b or later; github.com/mattermost/mattermost-server (Go): upgrade to 10.11.4, 10.11.4+incompatible or later; github.com/mattermost/mattermost-server/v5 (Go): upgrade to 5.3.2-0.20250905150616-ba86dfc5876b or later; github.com/mattermost/mattermost-server/v6 (Go): upgrade to 5.3.2-0.20250905150616-ba86dfc5876b or later; github.com/mattermost/mattermost/server/v8 (Go): upgrade to 8.0.0-20250905150616-ba86dfc5876b, 8.0.0-20251212204551-54f2e9b4afd5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve. **Am I affected by CVE-2025-11777?** 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. ## How to fix - github.com/mattermost/mattermost (Go): upgrade to 5.3.2-0.20250905150616-ba86dfc5876b or later ```sh go get github.com/mattermost/mattermost@v5.3.2-0.20250905150616-ba86dfc5876b ``` - github.com/mattermost/mattermost-server (Go): upgrade to 10.11.4, 10.11.4+incompatible or later ```sh go get github.com/mattermost/mattermost-server@v10.11.4+incompatible ``` - github.com/mattermost/mattermost-server/v5 (Go): upgrade to 5.3.2-0.20250905150616-ba86dfc5876b or later ```sh go get github.com/mattermost/mattermost-server/v5@v5.3.2-0.20250905150616-ba86dfc5876b ``` - github.com/mattermost/mattermost-server/v6 (Go): upgrade to 5.3.2-0.20250905150616-ba86dfc5876b or later ```sh go get github.com/mattermost/mattermost-server/v6@v5.3.2-0.20250905150616-ba86dfc5876b ``` - github.com/mattermost/mattermost/server/v8 (Go): upgrade to 8.0.0-20250905150616-ba86dfc5876b, 8.0.0-20251212204551-54f2e9b4afd5 or later ```sh go get github.com/mattermost/mattermost/server/v8@v8.0.0-20251212204551-54f2e9b4afd5 ``` ## Affected products - github.com/mattermost/mattermost (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250905150616-ba86dfc5876b - github.com/mattermost/mattermost-server (Go) SEMVER:introduced=10.11.0,fixed=10.11.4, SEMVER:introduced=10.5.0+incompatible,fixed=10.5.12+incompatible,introduced=10.11.0+incompatible,fixed=10.11.4+incompatible - github.com/mattermost/mattermost-server/v5 (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250905150616-ba86dfc5876b - github.com/mattermost/mattermost-server/v6 (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250905150616-ba86dfc5876b - github.com/mattermost/mattermost/server/v8 (Go) SEMVER:introduced=0,fixed=8.0.0-20250905150616-ba86dfc5876b, SEMVER:introduced=0,fixed=8.0.0-20251212204551-54f2e9b4afd5 - github.com/mattermost/mattermost/v5 (Go) SEMVER:introduced=0 - Mattermost Server ## Identifiers - CVE-2025-11777 - GHSA-mqcj-8c2g-h97q - GO-2025-4122 ## Related threats - [Mattermost CSRF via Agents plugin mention reminder validation](https://junglewise.ai/threats/cve-2026-93851-mattermost-versions-11-9-x-11-9-1-11-8-x-11-8-5-11-7-x-11-7-10) - [Mattermost denial of service via PDF text extraction memory exhaustion](https://junglewise.ai/threats/cve-2026-93850-mattermost-versions-11-9-x-11-9-1-11-8-x-11-8-5-11-7-x-11-7-10-11) - [Mattermost denial of service in WebSocket msgpack decoder](https://junglewise.ai/threats/cve-2026-93849-mattermost-versions-11-9-x-11-9-1-11-8-x-11-8-5-11-7-x-11-7-10-11) - [Mattermost information disclosure in post deletion events](https://junglewise.ai/threats/cve-2026-19621-mattermost-versions-11-10-x-11-10-0-11-7-x-11-7-9-11-9-x-11-9-1) - [Mattermost authentication token leak in server logs](https://junglewise.ai/threats/cve-2026-19600-mattermost-versions-11-9-x-11-9-1-11-8-x-11-8-5-11-7-x-11-7-10-11)