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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| socketio | socket.io | >= 6.5.0, < 6.6.7 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | dotnet8.0 +4 | 8.0.128-1.hum1 | RHSA-2026:26994 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | jupyter-base-notebook | 7.6.3-r2 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| npm | engine.io | >= 6.5.0, < 6.6.7 | 6.6.7 | GHSA-gr94-w7qr-f4j3 |
Advisories 1
- RHSA-2026:26994 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026