GHSA-wvhx-q427-fgh3
Arbitrary HTML present after sanitization because of unicode normalization
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.
Blast Radius
html-sanitizerReal-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
Impact
If using keep_typographic_whitespace=False (which is the default), the sanitizer normalizes unicode to the NFKC form at the end. Some unicode characters normalize to chevrons; this allows specially crafted HTML to escape sanitization.
Patches
The problem has been fixed in 2.4.2.
Workarounds
Set keep_typographic_whitespace=True explicitly, or normalize to NFKC yourself earlier.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | html-sanitizer | all versions | 2.4.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for html-sanitizer. 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 html-sanitizer to 2.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wvhx-q427-fgh3 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-wvhx-q427-fgh3 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-wvhx-q427-fgh3. 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-wvhx-q427-fgh3 in your dependencies?
O3 detects GHSA-wvhx-q427-fgh3 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.