CVE-2025-55166 — enshrined/svg-sanitize
Fix: darylldoyle/svg-sanitizer@5a0a1eaCVE-2025-55166 is a Cross-site Scripting (XSS) vulnerability in enshrined/svg-sanitize. A fix is available for enshrined/svg-sanitize — see the affected versions and patch details below.
svg-sanitizer By-Passing Attribute Sanitization
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-55166.
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
enshrined/svg-sanitizeReal-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
savg-sanitizer is a PHP SVG/XML sanitizer. Prior to version 0.22.0, the sanitization logic in the cleanXlinkHrefs method only searches for lower-case attribute name, which allows to by-pass the isHrefSafeValue check. As a result this allows cross-site scripting or linking to external domains. This issue has been patched in version 0.22.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | enshrined/svg-sanitize | all versions | 0.22.0composer require enshrined/svg-sanitize:^0.22.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for enshrined/svg-sanitize, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update enshrined/svg-sanitize to 0.22.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-55166 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-55166 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-55166. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-55166 in your dependencies?
O3 Security finds CVE-2025-55166 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.