GHSA-hmr5-2xcr-v8pp
Fix: symfony/symfony@863aa81GHSA-hmr5-2xcr-v8pp is a Cross-site Scripting (XSS) vulnerability in symfony/symfony. O3 Security confirms whether GHSA-hmr5-2xcr-v8pp is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Symfony Vulnerable to stored XSS in WebProfiler CodeExtension::fileExcerpt() — Unescaped Non-PHP File Rendering
Exploitation Status
No confirmed exploitation observed yet
- 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-hmr5-2xcr-v8pp.
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/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/twig-bridge🐘symfony/web-profiler-bundle🐘symfony/web-profiler-bundleReal-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 profiler, a development only debug UI, renders source-code excerpts on several pages using Twig's custom file_excerpt filter. This filter renders PHP files via highlight_string() (which escapes HTML), but renders non-PHP files by splitting on \n and interpolating each line directly into <code>{$line}</code> with no escaping.
An attacker who can write arbitrary bytes into any file under the project root (including e.g. var/log/dev.log), achieves stored XSS against any developer who later opens that file in the profiler.
Resolution
The file_excerpt filter now properly escapes each line of non-PHP files using htmlspecialchars() before concatenating them.
The patch for this issue is available here for branch 6.4.
Credits
Symfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/symfony | ≥ 6.4.24&&< 6.4.40 | 6.4.40 |
| 🐘Packagist | symfony/symfony | ≥ 7.2.9&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/symfony | ≥ 8.0.0&&< 8.0.12 | 8.0.12 |
| 🐘Packagist | symfony/twig-bridge | ≥ 6.4.24&&< 6.4.40 | 6.4.40 |
| 🐘Packagist | symfony/web-profiler-bundle | ≥ 7.2.9&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/web-profiler-bundle | ≥ 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/symfony. 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/symfony to 6.4.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hmr5-2xcr-v8pp 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-hmr5-2xcr-v8pp 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-hmr5-2xcr-v8pp. 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-hmr5-2xcr-v8pp in your dependencies?
O3 detects GHSA-hmr5-2xcr-v8pp across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.