{"id":"CVE-2026-20927","aliases":["EUVD-2026-2128","GHSA-j925-72mv-w4rf"],"status":"published","title":"Windows SMB Server Denial of Service Vulnerability","description":"Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to deny service over a network.","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00909,"percentile":0.60389,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-362"],"published":"2026-01-13T17:56:42Z","modified":"2026-07-30T21:17:09Z","products":[{"vendor":"microsoft","product":"windows 10 version 1607"},{"vendor":"microsoft","product":"windows 10 version 1809"},{"vendor":"microsoft","product":"windows 10 version 21h2"},{"vendor":"microsoft","product":"windows 10 version 22h2"},{"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 server 2008 r2 service pack 1"},{"vendor":"microsoft","product":"windows server 2008 r2 service pack 1 (server core installation)"},{"vendor":"microsoft","product":"windows server 2008 service pack 2"},{"vendor":"microsoft","product":"windows server 2008 service pack 2 (server core installation)"},{"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_10_1607"},{"vendor":"microsoft","product":"windows_10_1809"},{"vendor":"microsoft","product":"windows_10_21h2"},{"vendor":"microsoft","product":"windows_10_22h2"},{"vendor":"microsoft","product":"windows_11_23h2"},{"vendor":"microsoft","product":"windows_11_24h2"},{"vendor":"microsoft","product":"windows_11_25h2"},{"vendor":"microsoft","product":"windows_server_2008"},{"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-2026-20927","tags":["vendor-advisory","patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-20927"},{"url":"https://github.com/advisories/GHSA-j925-72mv-w4rf"}],"sources":{"cve":[{"id":"CVE-2026-20927","title":"Windows SMB Server Denial of Service Vulnerability","description":"Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to deny service over a network.","status":"published","published":"2026-01-13T17:56:42.801Z","modified":"2026-07-30T20:46:58.173Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"medium","assessor":"cna"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T13:35:44.571002Z"}],"euvd":[{"id":"EUVD-2026-2128","description":"Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to deny service over a network.","status":"published","published":"2026-01-13T17:56:42Z","modified":"2026-07-30T20:46:58Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"medium"}],"updated_at":"2026-11-02T18:02:27.233735Z"}],"ghsa":[{"id":"GHSA-j925-72mv-w4rf","title":"Concurrent execution using shared resource with improper synchronization ('race condition') in...","description":"Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to deny service over a network.","status":"published","published":"2026-01-13T18:31:10Z","modified":"2026-01-13T18:31:19Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T15:05:35.156514Z"}],"nvd":[{"id":"CVE-2026-20927","description":"Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to deny service over a network.","status":"published","published":"2026-01-13T18:16:19.65Z","modified":"2026-07-30T21:17:09.487Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T14:12:04.066712Z"}]}}