Is CVE-2026-118264 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-118264 being exploited in the wild.

How severe is CVE-2026-118264?

Informational severity, published 28 October 2026.

Which products and versions are affected?

github.com/labstack/echo/v4 (Go) SEMVER:introduced=4.0.0,fixed=4.16.1; github.com/labstack/echo/v5 (Go) SEMVER:introduced=5.0.0,fixed=5.4.1; Labstack Echo 4.0.0 to 4.16.0, 5.0.0 to 5.4.0.

Is there a fix for CVE-2026-118264?

Yes. github.com/labstack/echo/v4 (Go): upgrade to 4.16.1 or later; github.com/labstack/echo/v5 (Go): upgrade to 5.4.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-118264 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-118264?

Check whether you run github.com/labstack/echo/v4 (Go), github.com/labstack/echo/v5 (Go) or Labstack Echo at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-118264: Echo Proxy middleware WebSocket upgrade validation bypass

CVE-2026-118264 · Severity: info · Published 2026-10-28

Echo is a Go web framework used to build HTTP services and APIs. The Proxy middleware component can be bypassed when handling WebSocket upgrade requests: if an upstream server rejects the upgrade, subsequent HTTP requests on that connection are sent directly to the upstream without passing through Echo's authentication or authorization checks. An attacker with access to a proxy route could exploit this to access protected resources on the backend server.

Technologies: github.com/labstack/echo/v4 (Go), github.com/labstack/echo/v5 (Go), Labstack Echo. Vendors: Go, Labstack.

Quick answers

Is CVE-2026-118264 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-118264 being exploited in the wild.
How severe is CVE-2026-118264?: Informational severity, published 28 October 2026.
Which products and versions are affected?: github.com/labstack/echo/v4 (Go) SEMVER:introduced=4.0.0,fixed=4.16.1; github.com/labstack/echo/v5 (Go) SEMVER:introduced=5.0.0,fixed=5.4.1; Labstack Echo 4.0.0 to 4.16.0, 5.0.0 to 5.4.0.
Is there a fix for CVE-2026-118264?: Yes. github.com/labstack/echo/v4 (Go): upgrade to 4.16.1 or later; github.com/labstack/echo/v5 (Go): upgrade to 5.4.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-118264 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-118264?: Check whether you run github.com/labstack/echo/v4 (Go), github.com/labstack/echo/v5 (Go) or Labstack Echo at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

github.com/labstack/echo/v4 (Go): upgrade to 4.16.1 or later
```
go get github.com/labstack/echo/v4@v4.16.1
```
github.com/labstack/echo/v5 (Go): upgrade to 5.4.1 or later
```
go get github.com/labstack/echo/v5@v5.4.1
```

Technical details

The Proxy middleware in Echo versions 4.0.0–4.16.0 and 5.0.0–5.4.0 fail to validate that an upstream accepted a WebSocket upgrade before establishing a tunnel. If the upstream returns a keep-alive HTTP response rejecting the upgrade, the middleware creates a raw tunnel for subsequent requests without routing them through Echo's middleware chain. This allows bypass of route-level authentication or authorization, provided the attacker can craft a rejected-upgrade scenario and the target backend lacks independent authorization checks.

Affected products

labstack Echo 4.0.0 to 4.16.0, 5.0.0 to 5.4.0

Identifiers

CVE-2026-118264
GHSA-cxf3-9h37-7rr8
GO-2026-6839

Timeline

2026-10-28: disclosed

References

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