# CVE-2026-19621: Mattermost leaks interactive-message integration secrets to non-admin users via post-deletion events and thread reads

> CVE-2026-19621: Mattermost leaks interactive-message integration secrets to non-admin users via post-deletion events and thread reads. CVSS 6.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-19621
Last updated: 2026-10-16T19:23:18Z

- Published: 2026-10-16 07:06 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: 0.25%, 16th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-200

## 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 strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain server-side webhook URLs and authentication context from interactive-message posts via the post\_deleted websocket event or the threads REST API.. Mattermost Advisory ID: MMSA-2026-00766

## 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-2026-19621)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-19621)
- [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-2026-19621 · Markdown: https://rewindex.com/cve/CVE-2026-19621.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-19621 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:16:25.854Z