{"cve":"CVE-2026-118264","nvd":{"published":"2026-10-28T19:17:31.237","modified":"2026-10-28T19:17:31.237","status":"Received","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.","cvss_v4":{"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","score":9.1},"cvss_v3":null,"cwes":["CWE-444","CWE-863"],"references":["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/releases/tag/v5.4.1","https://github.com/labstack/echo/security/advisories/GHSA-cxf3-9h37-7rr8"],"products":[],"source":"nvd","synced_at":"2026-10-28T19:37:43.506563291+00:00"},"epss":null,"kev":null,"osv":[{"id":"GHSA-cxf3-9h37-7rr8","url":"https://osv.dev/vulnerability/GHSA-cxf3-9h37-7rr8","summary":"Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls","modified":"2026-10-28T19:30:04.341060872Z","packages":[{"ecosystem":"Go","name":"github.com/labstack/echo/v4","purl":"pkg:golang/github.com/labstack/echo/v4","ranges":[">=4.0.0 <4.16.1"],"fixed":["4.16.1"]},{"ecosystem":"Go","name":"github.com/labstack/echo/v5","purl":"pkg:golang/github.com/labstack/echo/v5","ranges":[">=5.0.0 <5.4.1"],"fixed":["5.4.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}