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TI-2023-14835 Aliases CVE-2023-31125GHSA-q9mw-68c2-j6m5

Uncaught exception in engine.io

Priority LOW 32CWE-248Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-248.

Summary

Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. An uncaught exception vulnerability was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. This impacts all the users of the `engine.io` package, including those who use depending packages like `socket.io`. This issue was fixed in version 6.4.2 of Engine.IO. There is no known workaround except upgrading to a safe version.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01327 71st percentileScored 2026-11-07
Fix Fixed engine.io (socketio): 6.4.2engine.io (npm): 6.4.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
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
socketioengine.io5.1.0 to before 6.4.26.4.2Patch availableCNA
—engine.io (npm)5.1.0 to before 6.4.26.4.2Patch availableGHSA-q9mw-68c2-j6m5
  • engine.io Vendorsocketio Affected 5.1.0 to before 6.4.2 Fixed in 6.4.2 Patch available CNA
  • engine.io (npm) Vendor— Affected 5.1.0 to before 6.4.2 Fixed in 6.4.2 Patch available GHSA-q9mw-68c2-j6m5

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*5.1.0 to before 6.4.2Vulnerablesocketio
  • cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:* Versions 5.1.0 to before 6.4.2 Vulnerable ·socketio

Remediation

  • Fix · CNA engine.io (socketio) Fixed in 6.4.2
  • Fix · GHSA-q9mw-68c2-j6m5 engine.io (npm) Fixed in 6.4.2 Advisory →

Vendor assessments

Red Hat

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

Not affected: 2 products
  • Red Hat JBoss Data Grid 7
  • Red Hat Quay 3

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-31125
  2. 2026-10-03 Alias added: GHSA-q9mw-68c2-j6m5

References

Patch 1

Advisory 2

Other 4

  • 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-2026-42593 Socket.IO: Engine.IO WebTransport SID DoS 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

Sources

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