GHSA-754h-5r27-7x3r
HIGHGHSA-754h-5r27-7x3r is a high-severity (CVSS 8) CWE-212 vulnerability in symfony/http-kernel. O3 Security confirms whether GHSA-754h-5r27-7x3r is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
RCE in Symfony
Blast Radius
symfony/http-kernel🐘symfony/http-kernel🐘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
The CachingHttpClient class from the HttpClient Symfony component relies on the HttpCache class to handle requests. HttpCache uses internal headers like X-Body-Eval and X-Body-File to control the restoration of cached responses. The class was initially written with surrogate caching and ESI support in mind (all HTTP calls come from a trusted backend in that scenario). But when used by CachingHttpClient and if an attacker can control the response for a request being made by the CachingHttpClient, remote code execution is possible.
Resolution
HTTP headers designed for internal use in HttpCache are now stripped from remote responses before being passed to HttpCache.
The patch for this issue is available here for the 4.4 branch.
Credits
I would like to thank Matthias Pigulla (webfactory GmbH) for reporting and fixing the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/http-kernel | ≥ 4.3.0&&< 4.4.13 | 4.4.13 |
| 🐘Packagist | symfony/http-kernel | ≥ 5.0.0&&< 5.1.5 | 5.1.5 |
| 🐘Packagist | symfony/symfony | ≥ 4.3.0&&< 4.4.13 | 4.4.13 |
| 🐘Packagist | symfony/symfony | ≥ 5.0.0&&< 5.1.5 | 5.1.5 |
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 4.4.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-754h-5r27-7x3r 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-754h-5r27-7x3r 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-754h-5r27-7x3r. 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-754h-5r27-7x3r in your dependencies?
O3 detects GHSA-754h-5r27-7x3r across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.