CVE-2026-24661: Mattermost MS Teams plugin doesn't limit the request body size on the /changes webhook endpoint

April 9, 2026 (updated April 29, 2026)

Mattermost Plugins versions <=2.1.3.0 fail to limit the request body size on the {{/changes}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and denial of service via sending an oversized JSON payload. Mattermost Advisory ID: MMSA-2026-00611.

References

github.com/advisories/GHSA-5rfv-h47g-xj42
github.com/mattermost/mattermost-plugin-msteams/commit/6fe4d295592ecc8767d67e69286cbeec01be3210
github.com/mattermost/mattermost-plugin-msteams/releases/tag/v2.3.2
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2026-24661

Code Behaviors & Features

Detect and mitigate CVE-2026-24661 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →