Symfony up to 5.4.51/6.4.39/7.4.11/8.0.11 Address src/Mime/Address.php address crlf injection

Summaryinfo

A vulnerability has been found in Symfony up to 5.4.51/6.4.39/7.4.11/8.0.11 and classified as critical. This issue affects some unknown processing of the file src/Mime/Address.php of the component Address. Performing a manipulation of the argument address results in crlf injection. This vulnerability is identified as CVE-2026-45067. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Symfony up to 5.4.51/6.4.39/7.4.11/8.0.11. It has been classified as critical. This affects an unknown part of the file src/Mime/Address.php of the component Address. The manipulation of the argument address with an unknown input leads to a crlf injection vulnerability. CWE is classifying the issue as CWE-93. The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

### 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](https://github.com/symfony/symfony/commit/dc2dbd29211eb4ddc451373fa1374fb926e94604) for branch 5.4. ### Credits We would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-45067 since 05/08/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

By approaching the search of inurl:src/Mime/Address.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 5.4.52, 6.4.40, 7.4.12 or 8.0.12 eliminates this vulnerability.

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Productinfo

Name

• Symfony

Version

• 5.4.0
• 5.4.1
• 5.4.2
• 5.4.3
• 5.4.4
• 5.4.5
• 5.4.6
• 5.4.7
• 5.4.8
• 5.4.9
• 5.4.10
• 5.4.11
• 5.4.12
• 5.4.13
• 5.4.14
• 5.4.15
• 5.4.16
• 5.4.17
• 5.4.18
• 5.4.19
• 5.4.20
• 5.4.21
• 5.4.22
• 5.4.23
• 5.4.24
• 5.4.25
• 5.4.26
• 5.4.27
• 5.4.28
• 5.4.29
• 5.4.30
• 5.4.31
• 5.4.32
• 5.4.33
• 5.4.34
• 5.4.35
• 5.4.36
• 5.4.37
• 5.4.38
• 5.4.39
• 5.4.40
• 5.4.41
• 5.4.42
• 5.4.43
• 5.4.44
• 5.4.45
• 5.4.46
• 5.4.47
• 5.4.48
• 5.4.49
• 5.4.50
• 5.4.51
• 6.4.0
• 6.4.1
• 6.4.2
• 6.4.3
• 6.4.4
• 6.4.5
• 6.4.6
• 6.4.7
• 6.4.8
• 6.4.9
• 6.4.10
• 6.4.11
• 6.4.12
• 6.4.13
• 6.4.14
• 6.4.15
• 6.4.16
• 6.4.17
• 6.4.18
• 6.4.19
• 6.4.20
• 6.4.21
• 6.4.22
• 6.4.23
• 6.4.24
• 6.4.25
• 6.4.26
• 6.4.27
• 6.4.28
• 6.4.29
• 6.4.30
• 6.4.31
• 6.4.32
• 6.4.33
• 6.4.34
• 6.4.35
• 6.4.36
• 6.4.37
• 6.4.38
• 6.4.39
• 7.4.0
• 7.4.1
• 7.4.2
• 7.4.3
• 7.4.4
• 7.4.5
• 7.4.6
• 7.4.7
• 7.4.8
• 7.4.9
• 7.4.10
• 7.4.11
• 8.0.0
• 8.0.1
• 8.0.2
• 8.0.3
• 8.0.4
• 8.0.5
• 8.0.6
• 8.0.7
• 8.0.8
• 8.0.9
• 8.0.10
• 8.0.11

License

• open-source

Website

• Product: https://github.com/symfony/symfony/

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