CRLF injection in Symfony - CVE-2026-45070
Published: May 21, 2026
Vulnerability identifier: #VU132062
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-45070
CWE-ID: CWE-93
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to inject arbitrary email headers.
The vulnerability exists due to improper neutralization of CRLF sequences in ParameterizedHeader parameter name handling when serializing structured email headers with user-controlled parameter names. A remote attacker can supply a crafted parameter name containing CRLF characters to inject arbitrary email headers.
The issue affects parameter names in structured headers such as Content-Type and Content-Disposition.
Affected software
Symfony
How to mitigate CVE-2026-45070
Install security update from vendor's website.
Symfony - addressed in versions 5.4.52, 6.4.40, 7.4.12, 8.0.12