CVE-2020-7662 is a high-severity (CVSS 7.5) vulnerability in websocket-extensions. 3 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2020-7662 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Regular Expression Denial of Service in websocket-extensions (NPM package)
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
websocket-extensionsnpmDescription
websocket-extensions npm module prior to 0.1.4 allows Denial of Service (DoS) via Regex Backtracking. The extension parser may take quadratic time when parsing a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. This could be abused by an attacker to conduct Regex Denial Of Service (ReDoS) on a single-threaded server by providing a malicious payload with the Sec-WebSocket-Extensions header.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | websocket-extensions | all versions | 0.1.4 |
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 websocket-extensions. 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 websocket-extensions to 0.1.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-7662 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-2020-7662 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-2020-7662. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
In both OpenShift Container Platform (OCP) and OpenShift ServiceMesh (OSSM), the grafana and prometheus containers are behind OpenShift OAuth restricting access to the vulnerable websocket-extension to authenticated users only, therefore the impact is Low.
Frequently Asked Questions
Is CVE-2020-7662 in your dependencies?
O3 detects CVE-2020-7662 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.