# CVE-2025-27936: Webhook Secret Exposure via Timing attack in MSteams plugin

> CVE-2025-27936: Webhook Secret Exposure via Timing attack in MSteams plugin. CVSS 5.3 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2025-27936
Last updated: 2026-06-17T09:04:25Z

- Published: 2025-04-16 09:14 UTC · Updated: 2026-06-17 09:04 UTC · Assigner: Mattermost
- CVSS: 5.3 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
- EPSS: 0.34%, 28th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-208

## Description

Mattermost Plugin MSTeams versions \<2.1.0 and Mattermost Server versions 10.5.x \<=10.5.1 with the MS Teams plugin enabled fail to perform constant time comparison on a MSTeams plugin webhook secret which allows an attacker to retrieve the webhook secret of the MSTeams plugin via a timing attack during webhook secret comparison.

## 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-2025-27936)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2025-27936)
- [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-2025-27936 · Markdown: https://rewindex.com/cve/CVE-2025-27936.md · JSON: https://rewindex.com/api/v1/cves/CVE-2025-27936 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:12:30.784Z