cyfenced.com →

[ CVE-2026-118264 · Published 28 Oct 2026 ]

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

CVSS 9.1 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Critical severity: CVSS 9.1

[ Description ]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.

[ Fixes ]Fixes and patches

  • github.com/labstack/echo/v4 4.16.1Fixed version · GitHub Advisories · go package github.com/labstack/echo/v4: upgrade to 4.16.1 or later (affected >= 4.0.0, < 4.16.1)
  • github.com/labstack/echo/v5 5.4.1Fixed version · GitHub Advisories · go package github.com/labstack/echo/v5: upgrade to 5.4.1 or later (affected >= 5.0.0, < 5.4.1)

[ Packages ]Affected open-source packages

  • github.com/labstack/echo/v4 goAffected >= 4.0.0, < 4.16.1 · fixed in 4.16.1 · GHSA-cxf3-9h37-7rr8
  • github.com/labstack/echo/v5 goAffected >= 5.0.0, < 5.4.1 · fixed in 5.4.1 · GHSA-cxf3-9h37-7rr8

[ References ]References