Critical 9.1Published Oct 28, 2026

CVE-2026-118264Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls

Updated under an hour ago (Oct 28, 2026, 5:00 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for labstack echo

Exploited in the last 30 days

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.

CVSS: 9.1 CRITICAL (v4.0, CNA)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
Weakness (CWE): CWE-444, CWE-863
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Received
Record last updated: Oct 28, 2026
First seen by InfoSec Signals: Oct 28, 2026

Affected products

Affected products

labstack echo labstack:echo (from the name)	from 4.0.0, < 4.16.1; from 5.0.0, < 5.4.1	CNA record

References

References

https://github.com/labstack/echo/security/advisories/GHSA-cxf3-9h37-7rr8	x-refsource-confirm
https://github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec	x-refsource-misc
https://github.com/labstack/echo/commit/3fb0ba7e17645bb65611e2a08875d0a2f65c421f	x-refsource-misc
https://github.com/labstack/echo/releases/tag/v4.16.1	x-refsource-misc
https://github.com/labstack/echo/releases/tag/v5.4.1	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.