CVE-2026-102600: CWE-20: Improper Input Validation in socketio socket.io
CVE-2026-102600 is a high-severity vulnerability in socket.io's @socket.io/cluster-engine prior to version 0.1.1. It involves improper input validation where attacker-controlled session IDs using special property names like __proto__ or constructor can traverse the prototype chain, causing the Node.js process to crash and resulting in denial of service. Applications not using @socket.io/cluster-engine are not affected. The issue is fixed in version 0.1.1.
AI Analysis
Technical Summary
Socket.IO's @socket.io/cluster-engine versions before 0.1.1 improperly validate input when looking up session IDs in clustered deployments. Specifically, it uses inherited object properties, allowing special property names such as __proto__ or constructor to resolve through the object prototype chain rather than identifying actual connected clients. This flaw causes the Node.js process to crash, leading to denial of service. The vulnerability is addressed in version 0.1.1.
Potential Impact
An attacker can cause the Node.js process running socket.io with @socket.io/cluster-engine to crash by sending specially crafted session IDs that exploit prototype pollution, resulting in denial of service. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade to @socket.io/cluster-engine version 0.1.1 or later, where this vulnerability is fixed. Applications not using @socket.io/cluster-engine are not affected and require no action.
CVE-2026-102600: CWE-20: Improper Input Validation in socketio socket.io
Description
CVE-2026-102600 is a high-severity vulnerability in socket.io's @socket.io/cluster-engine prior to version 0.1.1. It involves improper input validation where attacker-controlled session IDs using special property names like __proto__ or constructor can traverse the prototype chain, causing the Node.js process to crash and resulting in denial of service. Applications not using @socket.io/cluster-engine are not affected. The issue is fixed in version 0.1.1.
CVSS v3.1
Score 7.5high
Affected software
socketio
socket.io
@socket.io
cluster-engine
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Socket.IO's @socket.io/cluster-engine versions before 0.1.1 improperly validate input when looking up session IDs in clustered deployments. Specifically, it uses inherited object properties, allowing special property names such as __proto__ or constructor to resolve through the object prototype chain rather than identifying actual connected clients. This flaw causes the Node.js process to crash, leading to denial of service. The vulnerability is addressed in version 0.1.1.
Potential Impact
An attacker can cause the Node.js process running socket.io with @socket.io/cluster-engine to crash by sending specially crafted session IDs that exploit prototype pollution, resulting in denial of service. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade to @socket.io/cluster-engine version 0.1.1 or later, where this vulnerability is fixed. Applications not using @socket.io/cluster-engine are not affected and require no action.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-09-29T14:18:02.920Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6abbda3cf7a7c54106914862
Added to database: 09/29/2026, 15:33:16 UTC
Last enriched: 09/29/2026, 15:47:40 UTC
Last updated: 09/29/2026, 16:07:46 UTC
Views: 4
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