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
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
ua-parser-jsnpmDescription
Description:
A regular expression denial of service (ReDoS) vulnerability has been discovered in ua-parser-js.
Impact:
This vulnerability bypass the library's MAX_LENGTH input limit prevention. By crafting a very-very-long user-agent string with specific pattern, an attacker can turn the script to get stuck processing for a very long time which results in a denial of service (DoS) condition.
Affected Versions:
From version 0.7.30 to before versions 0.7.33 / 1.0.33.
Patches:
A patch has been released to remove the vulnerable regular expression, update to version 0.7.33 / 1.0.33 or later.
References:
Regular expression Denial of Service - ReDoS
Credits:
Thanks to @Snyk who first reported the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ua-parser-js | ≥ 0.7.30&&< 0.7.33 | 0.7.33 |
| 📦npm | ua-parser-js | ≥ 0.8.0&&< 1.0.33 | 1.0.33 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ua-parser-js. 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 ua-parser-js to 0.7.33 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fhg7-m89q-25r3 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-fhg7-m89q-25r3 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-fhg7-m89q-25r3. 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-fhg7-m89q-25r3 in your dependencies?
O3 detects GHSA-fhg7-m89q-25r3 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.