Medium, CVSS 6.6PackagistPublished
Symfony's Mailjet Mailer Webhook Parser Never Verifies the Configured Secret — Unauthenticated Webhook Event Injection
CVE-2026-45754 · GHSA-64hg-93w9-fc35
- Affected
- Packagist symfony/mailjet-mailer >= 6.4.0, < 6.4.40; >= 7.0.0, < 7.4.12; >= 8.0.0, < 8.0.12
- Fixed in
- 8.0.127.4.126.4.40· Vendor fix available
- Issue
- The Mailjet mailer bridge and the LOX24 SMS notifier bridge both ship webhook request parsers used to authenticate and decode the event callbacks each provider POSTs to an application's webhook endpoint. Their doParse(Request $request, #[\SensitiveParameter] string $secret) methods receive the configured webhook secret but never read it; they convert and return the payload unconditionally. As a result, an application that wires up either webhook endpoint accepts any POST to that URL, even when a webhook secret is configured (the recommended setup). An attacker who knows the endpoint exists can submit forged event payloads, fake bounce / blocked / spam / open / click / delivery events, leading to suppression-list corruption, delivery-metrics fraud, etc. Resolution MailjetRequestParser::doParse() now rejects the request unless it carries the expected HTTP Basic credentials, Mailjet's webhook authentication mechanism, using a constant-time comparison. The configured webhook…
Recommended action: Upgrade to 8.0.12, 7.4.12 or 6.4.40 by release line, then redeploy and verify.A vendor fix does not resolve your finding until you verify it in your own systems.