GHSA-57qw-cc2g-pv5p is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in lxml. 4 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-57qw-cc2g-pv5p is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
lxml Cross-site Scripting Via Control Characters
Real-World Exposure
lxmlReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Incomplete blacklist vulnerability in the lxml.html.clean module in lxml before 3.3.5 allows remote attackers to conduct cross-site scripting (XSS) attacks via control characters in the link scheme to the clean_html function.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | lxml | all versions | 3.3.5 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
lxml - 'clean_html' Security Bypass
by Maksim Kochkin · Apr 15, 2014
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for lxml. 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 lxml to 3.3.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-57qw-cc2g-pv5p 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-57qw-cc2g-pv5p 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-57qw-cc2g-pv5p. 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-57qw-cc2g-pv5p in your dependencies?
O3 detects GHSA-57qw-cc2g-pv5p across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.