{"id":"CVE-2026-103577","aliases":["EUVD-2026-100390","GHSA-74jh-9hhr-rxh5"],"status":"published","title":"Microsoft QUIC Security Feature Bypass Vulnerability","description":"Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to bypass a security feature over a network.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:H/E:U/RL:O/RC:C","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00574,"percentile":0.47874,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-453"],"published":"2026-10-13T19:01:36Z","modified":"2026-11-10T20:46:32Z","products":[{"vendor":"microsoft","product":"windows 11 version 23h2"},{"vendor":"microsoft","product":"windows 11 version 24h2"},{"vendor":"microsoft","product":"windows 11 version 25h2"},{"vendor":"microsoft","product":"windows 11 version 26h1"},{"vendor":"microsoft","product":"windows 11 version 26h2"},{"vendor":"microsoft","product":"windows server 2022"},{"vendor":"microsoft","product":"windows server 2025"},{"vendor":"microsoft","product":"windows server 2025 (server core installation)"},{"vendor":"microsoft","product":"windows_11_23h2"},{"vendor":"microsoft","product":"windows_11_24h2"},{"vendor":"microsoft","product":"windows_11_25h2"},{"vendor":"microsoft","product":"windows_11_26h1"},{"vendor":"microsoft","product":"windows_11_26h2"},{"vendor":"microsoft","product":"windows_server_2022"},{"vendor":"microsoft","product":"windows_server_2025"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-103577","tags":["vendor-advisory","patch","Patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-103577"},{"url":"https://github.com/advisories/GHSA-74jh-9hhr-rxh5"}],"sources":{"cve":[{"id":"CVE-2026-103577","title":"Microsoft QUIC Security Feature Bypass Vulnerability","description":"Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to bypass a security feature over a network.","status":"published","published":"2026-10-13T19:01:36.543Z","modified":"2026-11-10T20:46:32.854Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:H/E:U/RL:O/RC:C","level":"high","assessor":"cna"}],"cwes":["CWE-453"],"updated_at":"2026-11-10T22:18:24.949973Z"}],"euvd":[{"id":"EUVD-2026-100390","description":"Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to bypass a security feature over a network.","status":"published","published":"2026-10-13T19:01:36Z","modified":"2026-11-10T20:46:32Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:H/E:U/RL:O/RC:C","level":"high"}],"updated_at":"2026-11-10T22:23:55.776344Z"}],"ghsa":[{"id":"GHSA-74jh-9hhr-rxh5","title":"Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to...","description":"Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to bypass a security feature over a network.","status":"published","published":"2026-10-13T21:33:03Z","modified":"2026-10-13T21:33:10Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:H","level":"high"}],"cwes":["CWE-453"],"updated_at":"2026-11-02T15:13:13.272556Z"}],"nvd":[{"id":"CVE-2026-103577","description":"Insecure default variable initialization in Microsoft QUIC allows an unauthorized attacker to bypass a security feature over a network.","status":"published","published":"2026-10-13T19:17:53.723Z","modified":"2026-10-27T17:26:13.76Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-453"],"updated_at":"2026-11-02T14:12:57.132005Z"}]}}