GHSA-6439-2f28-8p8q
Fix: symfony/symfony@fa8d5c6GHSA-6439-2f28-8p8q is a CWE-863 vulnerability in symfony/http-kernel. O3 Security confirms whether GHSA-6439-2f28-8p8q is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Symfony's HEAD Request Bypasses methods: ['GET'] Filter in #[IsGranted] / #[IsSignatureValid] / #[IsCsrfTokenValid]
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-6439-2f28-8p8q.
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/http-kernel🐘symfony/http-kernel🐘symfony/security-http🐘symfony/security-http🐘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's #[IsGranted('...')], #[IsSignatureValid], and #[IsCsrfTokenValid(...)] attributes allow you to define a methods: [...] argument to only enforce these checks for the listed HTTP methods and skip them otherwise. E.g. an attribute defining methods: ['GET'] would be ignored for a HEAD request.
On the other hand, Symfony's router (and HTTP semantics generally) serves HEAD requests using the GET handler. Therefore, a controller protected by e.g. #[IsGranted('ROLE_ADMIN', methods: ['GET'])] can be reached via HEAD with the authorization check silently skipped.
Even if the HEAD request won't get any response content, response headers leak (Content-Length, Location, custom headers). Also, the controller still executes and any side effects (DB writes, state changes) occur.
Resolution
When adding GET in the methods option of these attributes, Symfony now also include the HEAD method automatically.
The patch for this issue is available here for branch 7.4.
Credits
Symfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and Alexandre Daubois for fixing it.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/http-kernel | ≥ 7.4.0&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/http-kernel | ≥ 8.0.0&&< 8.0.12 | 8.0.12 |
| 🐘Packagist | symfony/security-http | ≥ 7.4.0&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/security-http | ≥ 8.0.0&&< 8.0.12 | 8.0.12 |
| 🐘Packagist | symfony/symfony | ≥ 7.4.0&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/symfony | ≥ 8.0.0&&< 8.0.12 | 8.0.12 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/http-kernel. 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/http-kernel to 7.4.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6439-2f28-8p8q 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-6439-2f28-8p8q 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-6439-2f28-8p8q. 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-6439-2f28-8p8q in your dependencies?
O3 detects GHSA-6439-2f28-8p8q across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.