Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls

Echo

Echo's Proxy middleware selected a raw tunnel when the client requested a WebSocket upgrade, before validating whether the configured upstream accepted it. If the upstream returned an ordinary HTTP response and kept the connection alive, subsequent HTTP requests on that connection were forwarded directly to the same upstream without…

Do this now

Upgrade Echo's labstack/echo/v4 to 4.16.1 or labstack/echo/v5 to 5.4.1 now.

Fix it

github.com/labstack/echo/v4 go

go get github.com/labstack/echo/v4@v4.16.1

github.com/labstack/echo/v5 go

go get github.com/labstack/echo/v5@v5.4.1

First seen: 23 Oct 2026
Last update: 26 Oct 2026, 19:17 UTC
Fixed in: github.com/labstack/echo/v4 4.16.1
github.com/labstack/echo/v5 5.4.1
Source: GitHub advisory
On the menu as: Go

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls
Severity: critical. Patch status: patched.
Affected: Echo
Fixed in: github.com/labstack/echo/v4 4.16.1, github.com/labstack/echo/v5 5.4.1

Echo's Proxy middleware selected a raw tunnel when the client requested a WebSocket upgrade, before validating whether the configured upstream accepted it. If the upstream returned an ordinary HTTP response and kept the connection alive, subsequent HTTP requests on that connection were forwarded directly to the same upstream without…

## Steps
1. Search every lockfile and manifest (package-lock.json, yarn.lock, pnpm-lock.yaml, requirements*.txt, poetry.lock, uv.lock, composer.lock, go.sum, Cargo.lock, Gemfile.lock) for `github.com/labstack/echo/v4`, `github.com/labstack/echo/v5`. For each hit, compare the installed version with the fix on the same major line: github.com/labstack/echo/v4 4.16.1, github.com/labstack/echo/v5 5.4.1. If it's lower, give the exact upgrade command for the package manager this repo uses.

## Fix by release line
| Line | State | Fix | Until then |
|---|---|---|---|
| github.com/labstack/echo/v4 >= 4.0.0 < 4.16.1 | fixed | 4.16.1 | — |
| github.com/labstack/echo/v5 >= 5.0.0 < 5.4.1 | fixed | 5.4.1 | — |

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://github.com/advisories/GHSA-cxf3-9h37-7rr8 https://github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec https://github.com/labstack/echo/commit/3fb0ba7e17645bb65611e2a08875d0a2f65c421f https://github.com/labstack/echo/releases/tag/v4.16.1 https://github.com/labstack/echo/security/advisories/GHSA-cxf3-9h37-7rr8
https://pwned.coffee/i/echo-rejected-websocket-upgrades-can-bypass-echo-route-level-access-cont

Receipt

Exploitation: No known exploitation
Fix by release line: Product Affected Fixed in Source
github.com/labstack/echo/v4 (go) >= 4.0.0, < 4.16.1 4.16.1 GitHub advisory checked 26 Oct
github.com/labstack/echo/v5 (go) >= 5.0.0, < 5.4.1 5.4.1 GitHub advisory checked 26 Oct
Score: GitHub advisory rating: critical. No CVSS published.
Last checked: 26 Oct 2026, 20:41 UTC

Product	Affected	Fixed in	Source
github.com/labstack/echo/v4 (go)	>= 4.0.0, < 4.16.1	4.16.1	GitHub advisory checked 26 Oct
github.com/labstack/echo/v5 (go)	>= 5.0.0, < 5.4.1	5.4.1	GitHub advisory checked 26 Oct

Sources: KEV – CVE record ✓ Vendor –

Sources

Wrong fix version, or a source we missed? Send it back to chef@pwned.coffee with the source, and we'll correct it here.

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