GHSA-qpmx-3rfj-7rhv CVE-2026-45067
Symfony has Email Header / SMTP Command Injection via CRLF in Symfony\Component\Mime\Address
- Severity
- 0.0 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.60%
- Chance of exploitation in the next 30 days. Higher than 48.62% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-93 Improper Neutralization of CRLF Sequences ('CRLF Injection')
- Fix
- Available
- 2 packages have a fixed version
Description
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.
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| symfony/mime | < 5.4.52 |
5.4.52 |
| symfony/mime | >= 6.0.0, < 6.4.40 |
6.4.40 |
| symfony/mime | >= 7.0.0, < 7.4.12 |
7.4.12 |
| symfony/mime | >= 8.0.0, < 8.0.12 |
8.0.12 |
| symfony/symfony | < 5.4.52 |
5.4.52 |
| symfony/symfony | >= 6.0.0, < 6.4.40 |
6.4.40 |
| symfony/symfony | >= 7.0.0, < 7.4.12 |
7.4.12 |
| symfony/symfony | >= 8.0.0, < 8.0.12 |
8.0.12 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
symfony/mime Packagist → 5.4.52
- composer
composer require symfony/mime:^5.4.52
symfony/symfony Packagist → 5.4.52
- composer
composer require symfony/symfony:^5.4.52
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- Low
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- High
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
Weakness
CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')
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.
How to prevent it
- Implementation: Avoid using CRLF as a special sequence.
- Implementation: Appropriately filter or quote CRLF sequences in user-controlled input.
References
Packages
Other links
- github.com/symfony/symfony/security/advisories/GHSA-qpmx-3rfj-7rhv
- github.com/symfony/symfony/commit/dc2dbd29211eb4ddc451373fa1374fb926e94604
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/mime/CVE-2026-4…
- github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-202…
- symfony.com/cve-2026-45067
- github.com/symfony/symfony/commit/a1c42cbe517bc146a54da7505a107ded317478fe
- github.com/symfony/symfony/releases/tag/v5.4.52
- github.com/symfony/symfony/releases/tag/v6.4.40
- github.com/symfony/symfony/releases/tag/v7.4.12
- github.com/symfony/symfony/releases/tag/v8.0.12
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-2v3c-qxhr-7vpv Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process | High | Also affects symfony/symfony |
| GHSA-r925-mgvr-h9cc Symfony: ReDoS in HeaderUtils::split() Reachable Through the Cache-Control Request Header | High | Also affects symfony/symfony |
| GHSA-h5x3-xfc9-m39h Symfony: UrlGenerator Dot-Segment Encoding Skips Every Other Chained `../` or `./` → Generated URL Collapses Off-Route Under RFC 3986 Normalization | Medium | Also affects symfony/symfony |
| GHSA-v3wm-qf9p-c549 Symfony: HtmlSanitizer URL Parser Deny Gates Underinclusive: Percent-Encoded BiDi Marks and Unicode Whitespace Bypass Visual-Spoofing Defense | Medium | Also affects symfony/symfony |
| GHSA-rrj9-5q2j-4gvr Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade | Medium | Also affects symfony/symfony |
| GHSA-38cx-cq6f-5755 Symfony: IpUtils::PRIVATE_SUBNETS Omits IPv6 Transition Forms (6to4, NAT64, Teredo, IPv4-compatible): SSRF Bypass in NoPrivateNetworkHttpClient | High | Also affects symfony/symfony |
| GHSA-6h46-9jf5-q59x Symfony: Security Firewall Bypass via failure_forward Subrequest: Unauthenticated Access to access_control-Protected GET Routes | High | Also affects symfony/symfony |
| GHSA-x5qj-865h-mgvm Symfony: HtmlSanitizer UrlAttributeSanitizer Misses URL Attributes | Medium | Also affects symfony/symfony |
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