CVE-2026-45067
MediumCVSS 6.3Exploitation Probability (EPSS)
Low risk46th percentile - higher than 46% of all known CVEs
Summary
A vulnerability in the Symfony Address component allows injection of email headers or SMTP commands via a specially crafted email address with a quoted local part containing newline characters. The Address constructor did not reject addresses containing CRLF, enabling an attacker to manipulate message content or the SMTP protocol.
Risk Assessment
The risk involves the ability to send emails with forged headers (e.g., Bcc) or execute unauthorized SMTP commands, potentially compromising the confidentiality, integrity, or availability of the organization's mail system.
Recommendation
Immediately update Symfony to a version containing the fix (commit dc2dbd29211eb4ddc451373fa1374fb926e94604 for branch 5.4) or apply the patch manually to prevent acceptance of addresses with line breaks.
Other vulnerabilities in Symfony
See all- CVE-2016-4423High
The attemptAuthentication function in Symfony before versions 2.3.41, 2.7.13, 2.8.6, and 3.0.6 does not limit the length of a username stored in a session. This allows remote attackers to cause a denial of service through a series of authentication attempts with long, non-existent usernames.
- CVE-2016-1902High
The nextBytes function in the SecureRandom class in Symfony before 2.3.37, 2.6.x before 2.6.13, and 2.7.x before 2.7.9 does not properly generate random numbers when used with PHP 5.x without the paragonie/random_compat library, and the openssl_random_pseudo_bytes function fails.
- CVE-2013-1397High
Symfony versions 2.0.x before 2.0.22, 2.1.x before 2.1.7, and 2.2.x are vulnerable to remote attacks that allow arbitrary PHP code execution via a serialized PHP object in the Yaml::parse or Yaml\Parser::parse functions.
- CVE-2013-1348High
The Yaml::parse function in Symfony 2.0.x before version 2.0.22 allows remote attackers to execute arbitrary PHP code via a PHP file, which is a different vulnerability than CVE-2013-1397.
- CVE-2026-47767Critical
A vulnerability in Symfony allows an attacker to manipulate the APP_ENV and APP_DEBUG environment variables via a crafted query string that bypasses the protection introduced in CVE-2024-50340. The issue stems from a discrepancy between parse_str() and the web SAPI, enabling attacker-controlled --env or --no-debug flags to be passed to the script.
- CVE-2026-45069Critical
In Symfony up to versions 6.4.40, 7.4.12, and 8.0.12, the OidcTokenHandler::verifyClaims() method registered audience (aud), issuer (iss), and expiry (exp) checkers but did not pass the mandatory claims list to ClaimCheckerManager::check(). This allowed a validly signed JWT missing those claims to pass verification.
- CVE-2026-45063Critical
A vulnerability in Symfony X509Authenticator allows an attacker with a trusted certificate to impersonate a victim by placing emailAddress= in another RDN value, such as CN, due to an unanchored regex.
- CVE-2016-2403Critical
Symfony before 2.8.6 and 3.x before 3.0.6 allows remote attackers to bypass authentication by logging in with an empty password and valid username, which triggers an unauthenticated bind.
- CVE-2026-48784Medium
A vulnerability in Symfony allows an attacker to manipulate URL paths via controlled route parameters. The UrlGenerator::doGenerate() function uses strtr() dot-segment encoding that skips every other chained ../ or ./ segment, enabling generation of URLs that collapse to a different path under RFC 3986 normalization.
- CVE-2026-48761Medium
In Symfony PHP framework from 6.1.0 to 6.4.41, 7.4.13, and 8.0.13, UrlAttributeSanitizer::getSupportedAttributes() omitted URL-bearing attributes on <object>, <applet>, <iframe>, and <img>, and <meta http-equiv="refresh"> URLs bypassed sanitization, allowing javascript: payloads. Fixed in versions 6.4.41, 7.4.13, and 8.0.13.
Original NVD description (English source)
### 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.