Description
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.
References (3)
Core 3
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3
X_Refsource_Misc x_refsource_misc
https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c79158c
X_Refsource_Misc x_refsource_misc
https://github.com/socketio/socket.io/releases/tag/[email protected]
Scores
CVSS v3
7.5
EPSS
0.0034
EPSS Percentile
26.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-20
Status
published
Products (2)
socket/engine.io
6.5.0 - 6.6.7
socketio/socket.io
>= 6.5.0, < 6.6.7
Published
Jul 08, 2026
Tracked Since
Jul 08, 2026