CVE-2023-31125

Uncaught exception in engine.io

MEDIUM
6.5
CVSS Score
Published: May 8, 2023 at 08:21 PM UTC
Updated: June 17, 2026 at 05:56 AM UTC
2 products affected across 2 vendorsEngine.ioEngine.io

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Severity
MEDIUM6.5
Exploit prediction
EPSS 1%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.1.0 ≤ v < 6.4.2
Affected range stops below 6.4.2, so it looks safe — our inference, not a vendor statement
v < 6.4.2
Affected range stops below 6.4.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-248NVD-CWE-Other

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