NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
📦
📦 npm
Not in CISA KEV
MEDIUM severity

CVE-2020-28481 — socket.io

MEDIUMFix: socketio/socket.io@f78a575

CVE-2020-28481 is a medium-severity (CVSS 4.3) CWE-346 vulnerability in socket.io. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for socket.io — see the affected versions and patch details below.

CORS misconfiguration in socket.io

Also known asGHSA-fxwf-4rqh-v8g3
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 30, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.7%probability of exploitation in next 30 days
Lower Risk+0.01%
Lower risk than most CVEs55th percentile — riskier than 55% of all scored CVEsHighest risk
0.00%0.41%0.83%1.24%0.2%0.7%Apr 26Aug 26Oct 26

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

1 pkg affected

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.

12Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream
socket.ionpm
25.9Mdownloads / week

Description

The package socket.io before 2.4.0 are vulnerable to Insecure Defaults due to CORS Misconfiguration. All domains are whitelisted by default.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmsocket.ioall versions2.4.0npm install socket.io@2.4.0

Affected Products

1 product · 1 configurations
Application
socket.iosocket
< 2.4.0
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

The package socket.io before 2.4.0 are vulnerable to Insecure Defaults d…

github.comNVDJan 2021

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for socket.io, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update socket.io to 2.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-28481 is resolved across your whole dependency graph.

  3. 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.

Frequently Asked Questions

The package socket.io before 2.4.0 are vulnerable to Insecure Defaults due to CORS Misconfiguration. All domains are whitelisted by default.
O3 Security · Impact-Aware SCA

Is CVE-2020-28481 in your dependencies?

Find it across npm, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2020-28481: socket.io — Fixed in 2.4.0