NPM · AUGUST 2026 · EARLY WARNING

Socket.IO Memory Exhaustion Vulnerability: Early Warning

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
Severity
HIGH
Affected component
socket.io (npm)
Affected versions
< 2.5.1 or >= 3.0.0, < 4.6.2 or < 2.4.0 or < 0.9.7
Patched version
4.2.7,3.4.5,3.3.6
GHSA-2M8V-J782-FHVR

An early warning has been issued for a memory exhaustion vulnerability in Socket.IO. Users of affected versions should assess their exposure and upgrade to patched versions.

What happened

An early warning has been issued for a vulnerability in Socket.IO that can lead to memory exhaustion. A specially crafted Socket.IO packet can make the server wait for a large number of binary attachments and buffer them, potentially causing the server to run out of memory. This vulnerability affects specific versions of socket.io and socket.io-client.

The affected versions of socket.io are < 2.5.1 or >= 3.0.0, < 4.6.2 or < 2.4.0 or < 0.9.7. The affected versions of socket.io-client are >=4.0.0,<4.2.7. Patched versions are available for both components.

What to do about it

How 0Day would have caught this

MATCHED TO YOUR ACTUAL DEPENDENCY GRAPH0Day matches every incoming threat signal against your GitHub organization’s full dependency graph, including transitive dependencies. If socket.io is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.

Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.

Frequently asked questions

Am I affected?

You are affected if you are using socket.io versions < 2.5.1 or >= 3.0.0, < 4.6.2 or < 2.4.0 or < 0.9.7, or socket.io-client versions >=4.0.0,<4.2.7.

What should I do right now?

Upgrade to the fixed versions of socket.io (4.2.7, 3.4.5, or 3.3.6) and socket.io-client (4.2.7).

Where can I find more information?

Consult the primary sources for more information: [GHSA-2m8v-j782-fhvr] Socket.IO: Zero-attachment Memory Exhaustion (https://github.com/socketio/socket.io/security/advisories/GHSA-2m8v-j782-fhvr).

Sources

Join the 0Day waitlist →

← Back to all threats