Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

CVE-2026-45067

Gravedad CVSS v4.0:
MEDIA
Tipo:
CWE-93 Neutralización incorrecta de secuencias de retornos de carro y saltos de linea (CRLF)
Fecha de publicación:
14/07/2026
Última modificación:
14/07/2026

Descripción

*** Pendiente de traducción *** ### Description<br /> <br /> `Symfony\Component\Mime\Address` is the value-object every Symfony Mailer address (to/cc/bcc/from/reply-to) flows through; its constructor is documented as validating the address and throwing on invalid input, so developers treat it as a security boundary.<br /> <br /> The constructor accepts email addresses whose local-part (the part before `@`) is an RFC-5322 *quoted string* containing raw `\r\n` bytes — e.g. `"x\r\nBcc: attacker@evil"@example.com`. The stored address is later emitted verbatim into (1) the rendered message headers and (2) `SmtpTransport`&amp;#39;s `MAIL FROM:` / `RCPT TO:` protocol lines, turning the embedded CRLF into a new mail header and/or a new SMTP command.<br /> <br /> ### Resolution<br /> <br /> The `Address` constructor now rejects addresses containing line breaks.<br /> <br /> The patch for this issue is available [here](https://github.com/symfony/symfony/commit/dc2dbd29211eb4ddc451373fa1374fb926e94604) for branch 5.4.<br /> <br /> ### Credits<br /> <br /> We would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.