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.
Published: 2026-10-28
Score: 9.1 Critical
EPSS: n/a
KEV: No
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No solution or workaround provided in the CVE record.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories
Source ID Title
Github GHSA Github GHSA GHSA-cxf3-9h37-7rr8 Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls
History

Wed, 28 Oct 2026 21:00:00 +0000

Type Values Removed Values Added
First Time appeared Labstack
Labstack echo
Vendors & Products Labstack
Labstack echo

Wed, 28 Oct 2026 19:15:00 +0000

Type Values Removed Values Added
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.
Title Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls
Weaknesses CWE-444
CWE-863
References
Metrics cvssV4_0

{'score': 9.1, '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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-28T19:03:01.533Z

Reserved: 2026-10-27T20:13:55.314Z

Link: CVE-2026-118264

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-28T19:17:31.237

Modified: 2026-10-28T19:17:31.237

Link: CVE-2026-118264

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-28T21:00:23Z

Weaknesses