CVE-2020-36049 is a high-severity (CVSS 7.5) CWE-770 vulnerability in socket.io-parser. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for socket.io-parser — see the affected versions and patch details below.
Resource exhaustion in socket.io-parser
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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.
socket.io-parsernpmDescription
The socket.io-parser npm package before versions 3.3.2 and 3.4.1 allows attackers to cause a denial of service (memory consumption) via a large packet because a concatenation approach is used.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | socket.io-parser | all versions | 3.3.2npm install socket.io-parser@3.3.2 |
| 📦npm | socket.io-parser | ≥ 3.4.0&&< 3.4.1 | 3.4.1npm install socket.io-parser@3.4.1 |
Affected Products
socket.io-parsersocketResearch 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 socket.io-parser, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update socket.io-parser to 3.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-36049 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2020-36049 in your dependencies?
Find it across npm, including transitive dependencies.