GHSA-wfpm-5gcm-94cg

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Source
https://github.com/advisories/GHSA-wfpm-5gcm-94cg
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-wfpm-5gcm-94cg/GHSA-wfpm-5gcm-94cg.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-wfpm-5gcm-94cg
Aliases
Published
2026-10-05T23:44:21Z
Modified
2026-10-06T00:00:08Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
Socket.IO: Prototype Pollution via Unsafe Client Session Lookup
Details

Impact

This is a prototype pollution / improper client lookup vulnerability in @socket.io/cluster-engine.

Servers using @socket.io/cluster-engine may be impacted when attacker-controlled session IDs are processed in clustered deployments. A malicious client could use special property names such as __proto__, constructor, or other inherited object keys as a session identifier, causing the server to read properties from the object prototype chain instead of only real connected clients.

The impact is denial of service through process crash.

Applications not using @socket.io/cluster-engine are not affected by this specific issue.

Affected versions:

  • @socket.io/cluster-engine@0.1.0

Patches

The issue was fixed in:

  • @socket.io/cluster-engine@0.1.1

Workarounds

If upgrading immediately is not possible, users can reduce exposure by:

  • Rejecting or sanitizing suspicious session IDs before they reach the cluster engine.
  • Running the cluster engine behind trusted infrastructure that prevents arbitrary clients from crafting raw Engine.IO session-related requests.

These workarounds are defense-in-depth only. Upgrading to a patched version is recommended.

Database specific 
{
    "cwe_ids":  [
        "CWE-20"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-10-05T23:44:21Z",
    "nvd_published_at":  "2026-09-29T16:17:06Z",
    "severity":  "HIGH"
}
References

Affected packages

npm / @socket.io/cluster-engine

Package

Name
@socket.io/cluster-engine
View open source insights on deps.dev
Purl
pkg:npm/%40socket.io/cluster-engine

Affected ranges

Type
SEMVER
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
0.1.1

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-wfpm-5gcm-94cg/GHSA-wfpm-5gcm-94cg.json"