GHSA-q8hg-pf8v-cxrv
HIGHGHSA-q8hg-pf8v-cxrv is a high-severity (CVSS 8.1) CWE-203 vulnerability in symfony/http-kernel. O3 Security confirms whether GHSA-q8hg-pf8v-cxrv is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Symfony Http-Kernel has non-constant time comparison in UriSigner
Blast Radius
symfony/http-kernel🐘symfony/http-kernel🐘symfony/http-kernel🐘symfony/http-kernel🐘symfony/symfony🐘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
When checking the signature of an URI (an ESI fragment URL for instance), the URISigner did not used a constant time string comparison function, resulting in a potential remote timing attack vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/http-kernel | ≥ 2.2.0&&< 2.8.52 | 2.8.52 |
| 🐘Packagist | symfony/http-kernel | ≥ 3.0.0&&< 3.4.35 | 3.4.35 |
| 🐘Packagist | symfony/http-kernel | ≥ 4.0.0&&< 4.2.12 | 4.2.12 |
| 🐘Packagist | symfony/http-kernel | ≥ 4.3.0&&< 4.3.8 | 4.3.8 |
| 🐘Packagist | symfony/symfony | ≥ 2.2.0&&< 2.8.52 | 2.8.52 |
| 🐘Packagist | symfony/symfony | ≥ 3.0.0&&< 3.4.35 | 3.4.35 |
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 2.8.52 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q8hg-pf8v-cxrv 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-q8hg-pf8v-cxrv 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-q8hg-pf8v-cxrv. 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-q8hg-pf8v-cxrv in your dependencies?
O3 detects GHSA-q8hg-pf8v-cxrv across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.