CVE-2026-45755CWE-306CWE-347

Symfony: Mailtrap Mailer Webhook Parser Never Verifies the X-Mt-Signature HMAC — Unauthenticated Webhook Event Injection

Medium · published July 14, 2026

CVSS v4.0
6.9
EPSS
0%
Percentile
17.8
In the wild
Unconfirmed
What it is

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 7.4.12 and 8.0.12, MailtrapRequestParser::doParse() received the configured webhook secret but ignored the X-Mt-Signature HMAC header, allowing unauthenticated POST requests to inject forged Mailtrap delivery, bounce, open, click, or spam events. This issue is fixed in versions 7.4.12 and 8.0.12.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
EPSS
0.00267 · 17.8th percentile
Weaknesses
CWE-306 · Missing Authentication for Critical Function; CWE-347 · Improper Verification of Cryptographic Signature
Published
2026-07-14T18:56Z
EPSS history
Timeline
  • 14 JUL 18:56Z
    Symfony: Mailtrap Mailer Webhook Parser Never Verifies the X-Mt-Signature HMAC — Unauthenticated Webhook Event Injection
    cvelistv5