Discourse - Unauthenticated Mailpace Webhook Bounce-Score Forgery

Discourse's WebhooksController contains a missing-authentication flaw caused by accepting requests to provider webhook endpoints including /webhooks/mailpace, SendGrid, Mailjet, Mandrill, Postmark, and SparkPost without validating a token when none is configured, which is the default state, letti...

CVE-2026-26077: Improper Authentication

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, several webhook endpoints SendGrid, Mailjet, Mandrill, Postmark, SparkPost in the WebhooksController accepted requests without a valid authentication token when no token was configured. This...