# CVE-2025-14350: server — Fix Available 🐹 🐹 Go Not in CISA KEV MEDIUM severity # CVE-2025-14350 — server MEDIUM [Fix: mattermost/mattermost@761e56b](https://github.com/mattermost/mattermost/commit/761e56bb11ccb751ddbe4bab5898ccc2b384fd82) CVE-2025-14350 is a medium-severity (CVSS 4.3) CWE-862 vulnerability in github.com/mattermost/mattermost/server/v8. A fix is available for github.com/mattermost/mattermost/server/v8 — see the affected versions and patch details below. Information disclosure via channel mentions in posts Also known as[GHSA-57cc-2pf4-mhmx](/vulnerability/GHSA-57cc-2pf4-mhmx)GO-2026-4521 Published Feb 16, 2026 Updated Oct 28, 2026 Affected 5 pkgs Patched 2 / 5 Exploits None indexed Exploitation data as of Nov 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS) ## Exploitation Status ### No confirmed exploitation observed yet - CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment. Exploitation and automatability from CISA’s SSVC triage for CVE-2025-14350. ## EPSS Exploitation Probability [via FIRST.org ↗](https://www.first.org/epss/) 0.2%probability of exploitation in next 30 days Lower Risk0.00% Lower risk than most CVEs9th percentile — riskier than 9% of all scored CVEsHighest risk 0.00%0.23%0.46%0.69%0.0%0.2%May 26Sep 26Nov 26 Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/). ## How urgent is this, really ## Where this sits among everything scored ## Real-World Exposure 5 pkgs affected 🐹`github.com/mattermost/mattermost/server/v8`🐹`github.com/mattermost/mattermost-server`🐹`github.com/mattermost/mattermost-server`🐹`github.com/mattermost/mattermost-server`🐹`github.com/mattermost/mattermost-server` Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems. ## Description Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate team membership when processing channel mentions which allows authenticated users to determine the existence of teams and their URL names via posting channel shortlinks and observing the channel\_mentions property in the API response. Mattermost Advisory ID: MMSA-2025-00563 ## Affected Packages 5 total 2 fixed Ecosystem Package Vulnerable range Fix 🐹Go `github.com/mattermost/mattermost/server/v8` all versions 8.0.0-20251209134645-761e56bb11cc`go get github.com/mattermost/mattermost/server/v8@v8.0.0-20251209134645-761e56bb11cc` 🐹Go `github.com/mattermost/mattermost-server` ≥ 11.1.0 No fix 🐹Go `github.com/mattermost/mattermost-server` ≥ 10.11.0 No fix 🐹Go `github.com/mattermost/mattermost-server` ≥ 11.2.0 No fix 🐹Go `github.com/mattermost/mattermost-server` all versions 5.3.2-0.20251209134645-761e56bb11cc`go get github.com/mattermost/mattermost-server@v5.3.2-0.20251209134645-761e56bb11cc` ## Affected Products 1 product · 3 configurations Application `mattermost server`mattermost ≥ 11.2.0 && < 11.2.2 range ## Detection & mitigation playbook Open-source dependency 1. ### Detect Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost/server/v8, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version. 2. ### Fix Update github.com/mattermost/mattermost/server/v8 to 8.0.0-20251209134645-761e56bb11cc or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-14350 is resolved across your whole dependency graph. 3. ### Workarounds Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used. ## Frequently Asked Questions Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate team membership when processing channel mentions which allows authenticated users to determine the existence of teams and their URL names via posting channel shortlinks and observing the channel\_mentions property in the API response. Mattermost Advisory ID: MMSA-2025-00563 O3 Security · Impact-Aware SCA ### Is CVE-2025-14350 in your dependencies? Find it across Go, including transitive dependencies. [Scan my dependencies](/book-demo) [How O3 SCA works](/impact-aware-sca)