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TI-2026-42593 Aliases CVE-2026-59724GHSA-gr94-w7qr-f4j3

Socket.IO: Engine.IO WebTransport SID DoS

Priority MEDIUM 40CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 1 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

Socket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 before 6.6.7, Engine.IO servers with WebTransport enabled can resolve a crafted session ID such as __proto__ through an inherited property of the clients object during WebTransport upgrade handling, causing a TypeError and denial of service. This issue is fixed in version 6.6.7.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00609 49th percentileScored 2026-11-07
Fix Partial socket.io (socketio): 6.6.7engine.io (npm): 6.6.7Red Hat: 1 advisoryRed Hat: 1 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
socketiosocket.io6.5.0 to before 6.6.76.6.7Patch availableCNA
—engine.io (npm)6.5.0 to before 6.6.76.6.7Patch availableGHSA-gr94-w7qr-f4j3
  • socket.io Vendorsocketio Affected 6.5.0 to before 6.6.7 Fixed in 6.6.7 Patch available CNA
  • engine.io (npm) Vendor— Affected 6.5.0 to before 6.6.7 Fixed in 6.6.7 Patch available GHSA-gr94-w7qr-f4j3

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*6.5.0 to before 6.6.7Vulnerablesocketio
  • cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:* Versions 6.5.0 to before 6.6.7 Vulnerable ·socketio

Remediation

  • Fix · CNA socket.io (socketio) Fixed in 6.6.7
  • Fix · GHSA-gr94-w7qr-f4j3 engine.io (npm) Fixed in 6.6.7 Advisory →

Red Hat 1 advisory

  • RHSA-2026:26994 Released 2026-06-18 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images dotnet-sdk-8.0-8.0.128-1.hum1@aarch64, dotnet-sdk-8.0-8.0.128-1.hum1@x86_64, dotnet-sdk-8.0-source-built-artifacts-8.0.128-1.hum1@aarch64 +6

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet
Red Hat Hardened ImagesFixed RHSA-2026:26994
Not affected: 1 product
  • Red Hat Hardened Images

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-59724
  2. 2026-10-03 Alias added: GHSA-gr94-w7qr-f4j3
  3. 2026-10-07 Affected versions changed · Red Hat

References

Patch 2

Advisory 1

Other 2

  • TI-2022-20281 Uncaught exception in engine.io CVSS 3.1HIGH 7.1
  • TI-2022-06052 Uncaught Exception in engine.io CVSS 3.1HIGH 7.5
  • TI-2026-42594 Socket.IO: Engine.IO Polling Transport Connection Exhaustion CVSS 3.1HIGH 7.5
  • TI-2020-18427 Engine.IO before 4.0.0 allows attackers to cause a denial of service (resource… CVSS 3.1HIGH 7.5
  • TI-2023-14835 Uncaught exception in engine.io CVSS 3.1MEDIUM 6.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences