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.
https://github.com/symfony/symfony/security/advisories/GHSA-vqc8-7275-q272
https://github.com/symfony/symfony/releases/tag/v8.0.12
https://github.com/symfony/symfony/releases/tag/v7.4.12
https://github.com/symfony/symfony/releases/tag/v6.4.40
https://github.com/symfony/symfony/releases/tag/v5.4.52
https://github.com/symfony/symfony/commit/e62ea217f8b4ca8ae922ad0f949e0c4dc1f9b613
Published: 2026-07-14
Updated: 2026-07-16
Base Score: 6.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Severity: Medium
Base Score: 6.3
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00056