{"id":"CVE-2026-19377","aliases":["EUVD-2026-101881","GHSA-v76q-8hm2-wrx6"],"status":"published","title":"Improper certificate validation in Cato Client tunnel handshake","description":"Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.","severity":{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00083,"percentile":0.00206,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-295"],"published":"2026-10-15T07:02:10Z","modified":"2026-10-16T20:04:29Z","products":[{"vendor":"cato networks","product":"cato client for android"},{"vendor":"cato networks","product":"cato client for ios"},{"vendor":"cato networks","product":"cato client for linux"},{"vendor":"cato networks","product":"cato client for macos"},{"vendor":"cato networks","product":"cato client for windows"}],"references":[{"url":"https://knowledge.catonetworks.com/docs/security-vulnerability-cve-2026-19377-that-impacts-cato-client-versions","tags":["vendor-advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19377"},{"url":"https://github.com/advisories/GHSA-v76q-8hm2-wrx6"}],"sources":{"cve":[{"id":"CVE-2026-19377","title":"Improper certificate validation in Cato Client tunnel handshake","description":"Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.","status":"published","published":"2026-10-15T07:02:10.937Z","modified":"2026-10-15T14:22:58.368Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T13:47:06.353366Z"}],"euvd":[{"id":"EUVD-2026-101881","description":"Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.","status":"published","published":"2026-10-15T07:02:10Z","modified":"2026-10-15T14:22:58Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T17:00:14.584665Z"}],"ghsa":[{"id":"GHSA-v76q-8hm2-wrx6","title":"Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle...","description":"Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.","status":"published","published":"2026-10-15T09:30:33Z","modified":"2026-10-15T09:30:37Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/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","level":"medium"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T15:13:35.252436Z"}],"nvd":[{"id":"CVE-2026-19377","description":"Improper certificate validation in the tunnel handshake in Cato Client allows a man-in-the-middle attacker to impersonate a Cato Point of Presence (PoP) server and intercept or modify tunnel traffic.","status":"published","published":"2026-10-15T07:17:59.143Z","modified":"2026-10-16T20:04:29.76Z","cvss":[{"version":"4.0","score":6,"vector":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/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","level":"medium","assessor":"secondary"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T14:12:59.328869Z"}]}}