CVE-2026-48747

MEDIUM6.3

Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade

Published Jul 14, 2026

Modified 1 months ago

Details

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 7.4.13 and 8.0.13, MailomatRequestParser::validateSignature() parsed X-MOM-Webhook-Signature as algo=signature and passed the request-selected algorithm to hash_hmac(), allowing a signature algorithm downgrade instead of enforcing Mailomat's documented SHA-256 webhook signature. This issue is fixed in versions 7.4.13 and 8.0.13.

References

WEB

https://github.com/symfony/symfony/commit/bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88

WEB

https://github.com/symfony/symfony/releases/tag/v7.4.13

WEB

https://github.com/symfony/symfony/releases/tag/v8.0.13

WEB

https://github.com/symfony/symfony/security/advisories/GHSA-rrj9-5q2j-4gvr

ADVISORY

https://www.cve.org/CVERecord?id=CVE-2026-48747

CVSS Analysis