{"id":"CVE-2026-118264","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-118264","generatedAt":"2026-11-04T11:56:56.484Z","title":"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.","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":"2026-10-28T19:17:31.000Z","lastModified":"2026-10-30T20:17:06.000Z","status":"Undergoing Analysis","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":9.1,"severity":"CRITICAL","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/M"},"cwe":["CWE-444","CWE-863"],"affected":[],"epss":{"score":0.0043,"percentile":0.37235,"date":"2026-11-03","history":[{"date":"2026-10-29","score":0.0043,"percentile":0.37154}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-28T19:17:31.000Z","detail":{"score":"9.1","severity":"CRITICAL","publishedAt":"2026-10-28T19:17:31.237Z"},"summary":"New CVE, critical severity (CVSS 9.1)."}],"references":[{"url":"https://github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec","source":"security-advisories@github.com"},{"url":"https://github.com/labstack/echo/commit/3fb0ba7e17645bb65611e2a08875d0a2f65c421f","source":"security-advisories@github.com"},{"url":"https://github.com/labstack/echo/releases/tag/v4.16.1","source":"security-advisories@github.com"},{"url":"https://github.com/labstack/echo/releases/tag/v5.4.1","source":"security-advisories@github.com"},{"url":"https://github.com/labstack/echo/security/advisories/GHSA-cxf3-9h37-7rr8","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-118264","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}