CVE-2026-48747
MEDIUMSymfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade
Title source: cnaDescription
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 (4)
Core 4
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/symfony/symfony/security/advisories/GHSA-rrj9-5q2j-4gvr
X_Refsource_Misc x_refsource_misc
https://github.com/symfony/symfony/commit/bdfe9fe0d94d33dfaca0bc2fe0b00b54767b0c88
X_Refsource_Misc x_refsource_misc
https://github.com/symfony/symfony/releases/tag/v7.4.13
X_Refsource_Misc x_refsource_misc
https://github.com/symfony/symfony/releases/tag/v8.0.13
Scores
CVSS v3
5.3
EPSS
0.0020
EPSS Percentile
9.8%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-347
CWE-757
Status
published
Products (5)
sensiolabs/symfony
7.2.0 - 7.4.13
symfony/mailomat-mailer
>= 7.2.0, < 7.4.12
symfony/mailomat-mailer
>= 8.0.0-BETA1, < 8.0.13
symfony/symfony
>= 7.2.0, < 7.4.12
symfony/symfony
>= 8.0.0-BETA1, < 8.0.13
Published
Jul 14, 2026
Tracked Since
Jul 15, 2026