All socket.io CVEs — Complete Vulnerability History

socket.io is the most widely-used WebSocket library for Node.js. Its main CVE is a ReDoS vulnerability in socket ID parsing.

npm 5M+ weekly downloads 2 CVEs total

Full CVE history

CVEYearSeverityDescriptionFix
CVE-2020-284692020HIGHReDoS via crafted socket IDFixed 2.4.0
CVE-2023-326952023HIGHReDoS via specially crafted socket.idFixed 4.6.2

Current safe version: 4.6.2

# Before
"socket.io": "4.6.0"
# After
"socket.io": "4.6.2"

Then run: npm install

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Common questions

Is socket.io ReDoS exploitable?
Yes — a malicious client can send a crafted socket ID that causes the server to hang during regex processing. In Node.js's single-threaded event loop, this can block all other connections.
Does this affect socket.io-client?
No — the ReDoS is server-side. The socket.io-client package is not affected.

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