CVE-2026-118264 Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-118264?
CVE-2026-118264 is a critical vulnerability in labstack echo, published on 28 Oct 2026.
Official description
Echo is a Go web framework. From 4.0.0 until 4.16.1 and 5.4.1, Echo's Proxy middleware selects a raw tunnel from a client WebSocket upgrade request before verifying that the configured upstream accepted the upgrade. If the upstream rejects the upgrade with an ordinary keep-alive response, later HTTP requests on the connection are sent directly to that upstream without passing through Echo's router or route-specific middleware. This can bypass authentication or authorization enforced only by Echo routes, but requires an accessible proxy route, a cooperating rejected-upgrade response, and a target without independent upstream authorization. This issue is fixed in 4.16.1 and 5.4.1.
Which versions are affected by CVE-2026-118264?
4 open source packages ship an affected version, including github.com/labstack/echo/v4 and github.com/labstack/echo/v5.
| Package | Affected | Fixed in |
|---|---|---|
github.com/labstack/echo/v4 Go | From 4.0.0 | 4.16.1 |
github.com/labstack/echo/v4 Go | From 4.0.0 | 4.16.1 |
github.com/labstack/echo/v5 Go | From 5.0.0 | 5.4.1 |
github.com/labstack/echo/v5 Go | From 5.0.0 | 5.4.1 |
How do I fix CVE-2026-118264?
Upgrade github.com/labstack/echo/v4 to 4.16.1 or later.
Is CVE-2026-118264 being exploited?
There is no known exploitation of CVE-2026-118264 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-118264, ECHO-e1b6-15b1-4b64, GHSA-cxf3-9h37-7rr8, ROOT-APP-GOBINARY-GHSA-cxf3-9h37-7rr8, UBUNTU-CVE-2026-118264.