GHSA-f5ww-cq3m-q3g7
HIGHSanitize vulnerable to Cross-site Scripting via insufficient neutralization of `style` element content
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
sanitizeReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Using carefully crafted input, an attacker may be able to sneak arbitrary HTML and CSS through Sanitize >= 3.0.0, < 6.0.2 when Sanitize is configured to use the built-in "relaxed" config or when using a custom config that allows style elements and one or more CSS at-rules. This could result in XSS (cross-site scripting) or other undesired behavior when the malicious HTML and CSS are rendered in a browser.
Patches
Sanitize >= 6.0.2 performs additional escaping of CSS in style element content, which fixes this issue.
Workarounds
Users who are unable to upgrade can prevent this issue by using a Sanitize config that doesn't allow style elements, using a Sanitize config that doesn't allow CSS at-rules, or by manually escaping the character sequence </ as <\/ in style element content.
Credit
This issue was found by @cure53 during an audit of a project that uses Sanitize and was reported by one of that project's maintainers. Thank you!
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | sanitize | ≥ 3.0.0&&< 6.0.2 | 6.0.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sanitize. 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 sanitize to 6.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f5ww-cq3m-q3g7 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-f5ww-cq3m-q3g7 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-f5ww-cq3m-q3g7. 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-f5ww-cq3m-q3g7 in your dependencies?
O3 detects GHSA-f5ww-cq3m-q3g7 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.