# CVE-2025-11777: Cross-team channel membership access

> CVE-2025-11777: Cross-team channel membership access. CVSS 3.1 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2025-11777
Last updated: 2026-10-19T13:10:00Z

- Published: 2025-11-13 17:32 UTC · Updated: 2026-10-19 13:10 UTC · Assigner: Mattermost
- CVSS: 3.1 (CVSS 3.1) · Severity: Low · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
- EPSS: 0.20%, 9th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-863

## Description

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

## Affected vendors and products

- Mattermost: Mattermost

## Tracked companies

- [Mattermost](https://rewindex.com/company/mattermost.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2025-11777)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2025-11777)
- [https://mattermost.com/security-updates](https://mattermost.com/security-updates)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2025-11777 · Markdown: https://rewindex.com/cve/CVE-2025-11777.md · JSON: https://rewindex.com/api/v1/cves/CVE-2025-11777 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:13:34.340Z