# CVE-2026-19541: Outgoing OAuth connection client secret exposure during connection validation

> CVE-2026-19541: Outgoing OAuth connection client secret exposure during connection validation. CVSS 6.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-19541
Last updated: 2026-10-16T19:23:18Z

- Published: 2026-10-16 06:54 UTC · Updated: 2026-10-16 19:23 UTC · Assigner: Mattermost
- CVSS: 6.5 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- EPSS: 0.22%, 12th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-201

## Description

Mattermost versions 11.9.x \<= 11.9.1, 11.8.x \<= 11.8.5, 11.7.x \<= 11.7.10, 11.10.x \<= 11.10.1 fail to require re-entry of the stored client secret when validating an outgoing OAuth connection, which allows an authenticated user with permission to manage outgoing OAuth connections to obtain the secret via pointing the token URL at an attacker-controlled endpoint and triggering validation.. Mattermost Advisory ID: MMSA-2026-00761

## 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-2026-19541)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-19541)
- [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-2026-19541 · Markdown: https://rewindex.com/cve/CVE-2026-19541.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-19541 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T04:04:41.239Z