GHSA-vqc8-7275-q272
GHSA-vqc8-7275-q272 is a CWE-93 vulnerability in symfony/mime. O3 Security confirms whether GHSA-vqc8-7275-q272 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Symfony has Email Header Injection via Non-Token Characters in Mime Parameter Names
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-vqc8-7275-q272.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
symfony/mime🐘symfony/symfony🐘symfony/mime🐘symfony/mime🐘symfony/mime🐘symfony/symfony🐘symfony/symfony🐘symfony/symfonyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Description
Symfony\Component\Mime\Header\ParameterizedHeader (and the related parameter handling reachable from Symfony\Component\Mime\Header\Headers) is responsible for serializing structured headers such as Content-Type and Content-Disposition, which carry key=value parameters (e.g. Content-Disposition: attachment; filename="x").
RFC 2045 / RFC 5322 require parameter names to be tokens: a restricted ASCII subset that excludes whitespace, CR/LF, and the tspecials set. Symfony's parameter handling validates and properly encodes parameter values, but does not validate parameter names: the supplied name is emitted verbatim into the serialized header.
A caller that derives a parameter name from untrusted input, e.g. an application that lets a user influence a Content-Disposition parameter name, can include \r\n or other non-token bytes inside the name, terminating the current header and injecting additional headers in the rendered message. This is the classic CRLF / header-injection primitive applied to the parameter-name slot.
Resolution
ParameterizedHeader now rejects parameter names that contain bytes outside the RFC token character class.
The patch for this issue is available here for branch 5.4.
Credits
Symfony would like to thank Fabian Fleischer for reporting the issue and Alexandre Daubois for fixing it.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/mime | all versions | 5.4.52 |
| 🐘Packagist | symfony/symfony | all versions | 5.4.52 |
| 🐘Packagist | symfony/mime | ≥ 6.0.0&&< 6.4.40 | 6.4.40 |
| 🐘Packagist | symfony/mime | ≥ 7.0.0&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/mime | ≥ 8.0.0&&< 8.0.12 | 8.0.12 |
| 🐘Packagist | symfony/symfony | ≥ 6.0.0&&< 6.4.40 | 6.4.40 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/mime. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update symfony/mime to 5.4.52 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vqc8-7275-q272 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-vqc8-7275-q272 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-vqc8-7275-q272. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-vqc8-7275-q272 in your dependencies?
O3 detects GHSA-vqc8-7275-q272 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.