CVE record
CVE-2026-45070
Symfony: Email Header Injection via Non-Token Characters in Mime Parameter Names
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Mime\Header\ParameterizedHeader validates and encodes parameter values but emits parameter names verbatim, allowing a caller that derives a parameter name from untrusted input to include CRLF or other non-token bytes and inject additional headers into rendered structured mail headers such as Content-Type or Content-Disposition. This issue is reported as fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
CVE evidence
Known exploitation
Not listed in fetched KEV catalog
Absence from the fetched catalog does not establish that exploitation has not occurred.
Severity
moderate
CVSS 6.3 · CVSS_V4
Affected packages
2
Supported package records returned by OSV. Vendor and product names are not used to infer matches.
OSV package mapping
Affected open-source packages
| Package | Ecosystem | Fixed versions |
|---|---|---|
| symfony/mime | composer | 5.4.52, 6.4.40, 7.4.12, 8.0.12 |
| symfony/symfony | composer | 5.4.52, 6.4.40, 7.4.12, 8.0.12 |