---
title: "CVE-2026-118264: Echo - Authentication Bypass"
description: "Echo 4.0.0 to 4.16.1 and 5.x before 5.4.1 contain an authentication bypass caused by Proxy middleware forwarding requests after upstream rejects WebSocket upgrade, letting attackers bypass Echo route authentication, exploit requires accessible proxy route and cooperating upstream."
url: https://panop.io/threat-heartbeat/CVE-2026-118264/
---

# CVE-2026-118264 Echo - Authentication Bypass

Echo 4.0.0 to 4.16.1 and 5.x before 5.4.1 contain an authentication bypass caused by Proxy middleware forwarding requests after upstream rejects WebSocket upgrade, letting attackers bypass Echo route authentication, exploit requires accessible proxy route and cooperating upstream.

CVSS base score 9.1 /10

Critical

CISA KEV

Not listed

Public exploit

None known

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-118264)

## Details

Type

Authentication Bypass

Impact

Broken Authentication

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Published

28 October 2026

Updated

29 October 2026

Weakness

[CWE-444](https://cwe.mitre.org/data/definitions/444.html)

## Vendor fix

Update to versions 4.16.1 or 5.4.1 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-118264](https://nvd.nist.gov/vuln/detail/CVE-2026-118264)
- [https://github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec](https://github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec)
- [https://github.com/labstack/echo/commit/3fb0ba7e17645bb65611e2a08875d0a2f65c421f](https://github.com/labstack/echo/commit/3fb0ba7e17645bb65611e2a08875d0a2f65c421f)
- [https://github.com/labstack/echo/releases/tag/v4.16.1](https://github.com/labstack/echo/releases/tag/v4.16.1)
- [https://github.com/labstack/echo/releases/tag/v5.4.1](https://github.com/labstack/echo/releases/tag/v5.4.1)
- [https://github.com/labstack/echo/security/advisories/GHSA-cxf3-9h37-7rr8](https://github.com/labstack/echo/security/advisories/GHSA-cxf3-9h37-7rr8)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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