# CVE-2026-18256: Private team metadata disclosure via the team search API

> CVE-2026-18256: Private team metadata disclosure via the team search API. CVSS 4.3 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-18256
Last updated: 2026-10-16T19:23:18Z

- Published: 2026-10-16 07:13 UTC · Updated: 2026-10-16 19:23 UTC · Assigner: Mattermost
- CVSS: 4.3 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- EPSS: 0.16%, 5th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-863

## Description

Mattermost versions 11.10.x \<= 11.10.0, 11.7.x \<= 11.7.9, 11.9.x \<= 11.9.1, 11.8.x \<= 11.8.5 fail to properly restrict private teams from public team search results, which allows an authenticated user without permission to list private teams to disclose the ID, name, and display name of private teams via a modified team search request. Mattermost Advisory ID: MMSA-2026-00748

## 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-2026-18256)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-18256)
- [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-2026-18256 · Markdown: https://rewindex.com/cve/CVE-2026-18256.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-18256 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:14:38.738Z