# CVE-2026-2454: DoS in Calls plugin via malformed msgpack in websocket request.

> CVE-2026-2454: DoS in Calls plugin via malformed msgpack in websocket request.. CVSS 5.8 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-2454
Last updated: 2026-06-17T10:30:58Z

- Published: 2026-03-16 20:10 UTC · Updated: 2026-06-17 10:30 UTC · Assigner: Mattermost
- CVSS: 5.8 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
- EPSS: 0.29%, 21th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-1287

## Description

Mattermost versions 11.3.x \<= 11.3.0, 11.2.x \<= 11.2.2, 10.11.x \<= 10.11.10 fail to handle incorrectly reported array lengths which allows malicious user to cause OOM errors and crash the server via sending corrupted msgpack frames within websocket messages to calls plugin. Mattermost Advisory ID: MMSA-2025-00537

## 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-2026-2454)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-2454)
- [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-2026-2454 · Markdown: https://rewindex.com/cve/CVE-2026-2454.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-2454 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:12:35.444Z