Mattermost MS Teams plugin doesn't limit the request body size on the /lifecycle webhook endpoint
Mattermost Plugins versions <=2.3.1 fail to limit the request body size on the {{/lifecycle}} 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-2026-00610.
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describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-21388US | medium6.5 | — | ||
Mattermost Plugins versions <=2.3.1 fail to limit the request body size on the {{/lifecycle}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and… | ||||
02
references
External citations — patches, advisories, analysis.
- https://github.com/mattermost/mattermost-plugin-msteamsPACKAGE
- https://github.com/mattermost/mattermost-plugin-msteams/commit/6fe4d295592ecc8767d67e69286cbeec01be3210WEB
- https://github.com/mattermost/mattermost-plugin-msteams/releases/tag/v2.3.2WEB
- https://mattermost.com/security-updatesWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-21388ADVISORY
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