# CVE-2025-11776: GO-2025-4126 - Mattermost fails to properly restrict access to archived channel search API in github.com/mattermost/mattermost Source: https://junglewise.ai/threats/cve-2025-11776-mattermost-fails-to-properly-restrict-access-to-archived-channel Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats Published: 2025-11-14 License: CC BY 4.0 with a link back CVE-2025-11776 · Severity: medium · CVSS 4.3 · Published 2025-11-14 Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the `/api/v4/teams/{team_id}/channels/search_archived` 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-2025-11776 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-11776 being exploited in the wild. **How severe is CVE-2025-11776?** Medium severity, with a CVSS score of 4.3, published 14 November 2025. **Which products and versions are affected?** github.com/mattermost/mattermost (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250815165020-c8d66301415d; github.com/mattermost/mattermost-server (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250815165020-c8d66301415d; github.com/mattermost/mattermost-server/v5 (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250815165020-c8d66301415d; github.com/mattermost/mattermost-server/v6 (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250815165020-c8d66301415d; and 2 more. **Is there a fix for CVE-2025-11776?** Yes. github.com/mattermost/mattermost (Go): upgrade to 5.3.2-0.20250815165020-c8d66301415d or later; github.com/mattermost/mattermost-server (Go): upgrade to 5.3.2-0.20250815165020-c8d66301415d or later; github.com/mattermost/mattermost-server/v5 (Go): upgrade to 5.3.2-0.20250815165020-c8d66301415d or later; github.com/mattermost/mattermost-server/v6 (Go): upgrade to 5.3.2-0.20250815165020-c8d66301415d or later; github.com/mattermost/mattermost/server/v8 (Go): upgrade to 8.0.0-20250815165020-c8d66301415d or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve. **Am I affected by CVE-2025-11776?** 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 5.3.2-0.20250815165020-c8d66301415d or later ```sh go get github.com/mattermost/mattermost@v5.3.2-0.20250815165020-c8d66301415d ``` - github.com/mattermost/mattermost-server (Go): upgrade to 5.3.2-0.20250815165020-c8d66301415d or later ```sh go get github.com/mattermost/mattermost-server@v5.3.2-0.20250815165020-c8d66301415d ``` - github.com/mattermost/mattermost-server/v5 (Go): upgrade to 5.3.2-0.20250815165020-c8d66301415d or later ```sh go get github.com/mattermost/mattermost-server/v5@v5.3.2-0.20250815165020-c8d66301415d ``` - github.com/mattermost/mattermost-server/v6 (Go): upgrade to 5.3.2-0.20250815165020-c8d66301415d or later ```sh go get github.com/mattermost/mattermost-server/v6@v5.3.2-0.20250815165020-c8d66301415d ``` - github.com/mattermost/mattermost/server/v8 (Go): upgrade to 8.0.0-20250815165020-c8d66301415d or later ```sh go get github.com/mattermost/mattermost/server/v8@v8.0.0-20250815165020-c8d66301415d ``` ## Affected products - github.com/mattermost/mattermost (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250815165020-c8d66301415d - github.com/mattermost/mattermost-server (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250815165020-c8d66301415d - github.com/mattermost/mattermost-server/v5 (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250815165020-c8d66301415d - github.com/mattermost/mattermost-server/v6 (Go) SEMVER:introduced=0, SEMVER:introduced=0,fixed=5.3.2-0.20250815165020-c8d66301415d - github.com/mattermost/mattermost/server/v8 (Go) SEMVER:introduced=0,fixed=8.0.0-20250815165020-c8d66301415d - github.com/mattermost/mattermost/v5 (Go) SEMVER:introduced=0 - Mattermost Server ## Identifiers - CVE-2025-11776 - GHSA-j6gg-r5jc-47cm - GO-2025-4126 ## 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)