CRLF Injection Affecting symfony package, versions <7.4.12+dfsg-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-SYMFONY-16896458
- published27 May 2026
- disclosed14 Jul 2026
Introduced: 27 May 2026
CVE-2026-45067 (opens in a new tab)How to fix?
Upgrade Debian:unstable symfony to version 7.4.12+dfsg-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream symfony package and not the symfony package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
Description
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.
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's MAIL FROM:<...> / RCPT TO:<...> protocol lines, turning the embedded CRLF into a new mail header and/or a new SMTP command.
Resolution
The Address constructor now rejects addresses containing line breaks.
The patch for this issue is available here for branch 5.4.
Credits
We would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.
References
- https://security-tracker.debian.org/tracker/CVE-2026-45067
- https://github.com/symfony/symfony/commit/a1c42cbe517bc146a54da7505a107ded317478fe
- https://github.com/symfony/symfony/releases/tag/v5.4.52
- https://github.com/symfony/symfony/releases/tag/v6.4.40
- https://github.com/symfony/symfony/releases/tag/v7.4.12
- https://github.com/symfony/symfony/releases/tag/v8.0.12
- https://github.com/symfony/symfony/security/advisories/GHSA-qpmx-3rfj-7rhv