CVE-2020-1920 is a high-severity (CVSS 7.5) CWE-1333 vulnerability in react-native. O3 Security confirms whether CVE-2020-1920 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Regular expression denial of service in react-native
Real-World Exposure
react-native📦react-nativeReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
A regular expression denial of service (ReDoS) vulnerability in the validateBaseUrl function can cause the application to use excessive resources, become unresponsive, or crash. This was introduced in react-native version 0.59.0 and fixed in version 0.64.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | react-native | ≥ 0.59.0&&< 0.62.3 | 0.62.3 |
| 📦npm | react-native | ≥ 0.63.0&&< 0.64.1 | 0.64.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-native. 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 react-native to 0.62.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-1920 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-2020-1920 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-2020-1920. 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-2020-1920 in your dependencies?
O3 detects CVE-2020-1920 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.