CVE-2026-21388

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...

CVE-2026-21388 Unbounded Request Body Read in MS Teams Plugin {{/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...

CVE-2026-21388

CVE-2026-21388 affects Mattermost Plugins versions