Socketio Socket.Io vulnerabilities

6 vulnerabilities

Known vulnerabilities in Socketio Socket.Io, newest first, with CVSS severity, EPSS, KEV listings, ransomware use and the affected versions.

7.5CVE-2026-102599chainguardcommercial-gitlab-rails-ee-19.2+16
EPSS score
0.58%
Socket.IO enables bidirectional and low-latency communication for every platform. From Engine.IO 6.6.0 until 6.6.10, a transport upgrade can independently derive an Engine.IO protocol revision from the upgrade request instead of enforcing the revision stored on the existing session. A malicious client can establish a valid session and send an upgrade request with a different or omitted EIO query parameter, attaching a transport with incompatible parser and heartbeat behavior. A crafted heartbeat packet can then trigger an uncaught exception and terminate the Node.js process, including when Engine.IO v3 compatibility is disabled because an omitted EIO value is interpreted as revision 3 on the affected path. This issue is fixed in Engine.IO 6.6.10.
7.3CVE-2024-38355Npmsocket.io+1
EPSS score
0.81%
Socket.IO is an open source, real-time, bidirectional, event-based, communication framework. A specially crafted Socket.IO packet can trigger an uncaught exception on the Socket.IO server, thus killing the Node.js process. This issue is fixed by commit `15af22fc22` which has been included in `socket.io@4.6.2` (released in May 2023). The fix was backported in the 2.x branch as well with commit `d30630ba10`. Users are advised to upgrade. Users unable to upgrade may attach a listener for the "error" event to catch these errors.
7.5CVE-2026-59724chainguardjupyter-base-notebook+5
EPSS score
0.61%
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.
7.5CVE-2026-102600@socket.iocluster-engine+2
EPSS score
0.37%
Socket.IO enables bidirectional and low-latency communication for every platform. Prior to 0.1.1, @socket.io/cluster-engine uses inherited object properties when looking up attacker-controlled session IDs in clustered deployments. Special property names such as __proto__ or constructor can resolve through the object prototype chain instead of identifying an actual connected client, causing the Node.js process to crash and resulting in denial of service. Applications that do not use @socket.io/cluster-engine are not affected. This issue is fixed in version 0.1.1.
7.5CVE-2026-69185chainguardgitlab-rails-ce-19.2+9
EPSS score
0.63%
Socket.IO enables bidirectional and low-latency communication for every platform. Prior to 4.2.7, 3.4.5, and 3.3.6, a specially crafted Socket.IO packet can make the server wait for a large number of binary attachments and buffer them, which can be exploited to make the server run out of memory. This vulnerability is fixed in 4.2.7, 3.4.5, and 3.3.6.
8.7CVE-2026-33151chainguardkatib-earlystopping+25
EPSS score
0.65%
Socket.IO is an open source, real-time, bidirectional, event-based, communication framework. Prior to versions 3.3.5, 3.4.4, and 4.2.6, a specially crafted Socket.IO packet can make the server wait for a large number of binary attachments and buffer them, which can be exploited to make the server run out of memory. This issue has been patched in versions 3.3.5, 3.4.4, and 4.2.6.