{"id":"CVE-2026-26154","aliases":["EUVD-2026-22376","GHSA-xm9h-x34f-j9hj"],"status":"published","title":"Windows Server Update Service (WSUS) Tampering Vulnerability","description":"Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.01064,"percentile":0.64941,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-20"],"published":"2026-04-14T16:56:58Z","modified":"2026-10-26T22:10:00Z","products":[{"vendor":"microsoft","product":"windows server 2012"},{"vendor":"microsoft","product":"windows server 2012 (server core installation)"},{"vendor":"microsoft","product":"windows server 2012 r2"},{"vendor":"microsoft","product":"windows server 2012 r2 (server core installation)"},{"vendor":"microsoft","product":"windows server 2016"},{"vendor":"microsoft","product":"windows server 2016 (server core installation)"},{"vendor":"microsoft","product":"windows server 2019"},{"vendor":"microsoft","product":"windows server 2019 (server core installation)"},{"vendor":"microsoft","product":"windows server 2022"},{"vendor":"microsoft","product":"windows server 2022, 23h2 edition (server core installation)"},{"vendor":"microsoft","product":"windows server 2025"},{"vendor":"microsoft","product":"windows server 2025 (server core installation)"},{"vendor":"microsoft","product":"windows_server_2012"},{"vendor":"microsoft","product":"windows_server_2016"},{"vendor":"microsoft","product":"windows_server_2019"},{"vendor":"microsoft","product":"windows_server_2022"},{"vendor":"microsoft","product":"windows_server_2022_23h2"},{"vendor":"microsoft","product":"windows_server_2025"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26154","tags":["vendor-advisory","patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26154"},{"url":"https://github.com/advisories/GHSA-xm9h-x34f-j9hj"}],"sources":{"cve":[{"id":"CVE-2026-26154","title":"Windows Server Update Service (WSUS) Tampering Vulnerability","description":"Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.","status":"published","published":"2026-04-14T16:56:58.935Z","modified":"2026-10-15T15:52:18.419Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"high","assessor":"cna"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T13:38:20.971157Z"}],"euvd":[{"id":"EUVD-2026-22376","description":"Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.","status":"published","published":"2026-04-14T16:56:58Z","modified":"2026-10-15T15:52:18Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"high"}],"updated_at":"2026-11-02T17:00:13.422137Z"}],"ghsa":[{"id":"GHSA-xm9h-x34f-j9hj","title":"Improper input validation in Windows Server Update Service allows an unauthorized attacker to...","description":"Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.","status":"published","published":"2026-04-14T18:30:37Z","modified":"2026-04-14T18:30:43Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T15:07:29.002055Z"}],"nvd":[{"id":"CVE-2026-26154","description":"Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.","status":"published","published":"2026-04-14T18:16:46.95Z","modified":"2026-10-26T22:10:00.163Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:12:14.748836Z"}]}}