CVE-2026-45070: Sensiolabs Symfony

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Mime\Header\ParameterizedHeader validates and encodes parameter values but emits parameter names verbatim, allowing a caller that derives a parameter name from untrusted input to include CRLF or other non-token bytes and inject additional headers into rendered structured mail headers such as Content-Type or Content-Disposition. This issue is reported as fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.

Affected products

• Sensiolabs Symfony: before 5.4.52 (fixed in 5.4.52); from 6.0.0, before 6.4.40 (fixed in 6.4.40); from 7.0.0, before 7.4.12 (fixed in 7.4.12); from 8.0.0, before 8.0.12 (fixed in 8.0.12)

Published 2026-07-14. Last modified 2026-07-16.