Improper Verification of Cryptographic Signature in Symfony - CVE-2026-45755
Published: May 21, 2026
Vulnerability identifier: #VU132056
CSH Severity: Medium
CVSS v4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-45755
CWE-ID: CWE-347
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: SensioLabs
Affected software:
Symfony
Symfony
Detailed vulnerability description
The vulnerability allows a remote attacker to inject forged webhook events.
The vulnerability exists due to improper verification of cryptographic signature in MailtrapRequestParser::doParse() when handling webhook POST requests. A remote attacker can send a specially crafted request to inject forged webhook events.
An application that exposes the webhook endpoint and has a signing secret configured will still accept unsigned or forged event payloads.
How to mitigate CVE-2026-45755
Install security update from vendor's website.