CVE-2021-43306
HIGHCVE-2021-43306 is a high-severity (CVSS 7.5) CWE-1333 vulnerability in jquery-validation. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2021-43306 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Regular expression denial of service in jquery-validation
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
jquery-validationnpmDescription
An exponential ReDoS (Regular Expression Denial of Service) can be triggered in the jquery-validation npm package, when an attacker is able to supply arbitrary input to the url2 method
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jquery-validation | all versions | 1.19.4 |
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 jquery-validation. 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 jquery-validation to 1.19.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-43306 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 CVE-2021-43306 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 CVE-2021-43306. 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-2021-43306 in your dependencies?
O3 detects CVE-2021-43306 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.