{"id":"CVE-2026-20810","state":"PUBLISHED","title":"Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability","description":"Free of memory not on the heap in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.","publishedAt":"2026-01-13T17:56:10.446Z","updatedAt":"2026-07-30T20:46:28.241Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","source":"microsoft"},"assigner":"microsoft","products":["Microsoft Windows 10 Version 1809","Microsoft Windows 10 Version 21H2","Microsoft Windows 10 Version 22H2","Microsoft Windows Server 2019","Microsoft Windows Server 2019 (Server Core installation)"],"affected":[{"vendor":"Microsoft","product":"Windows 10 Version 1809","versions":[{"version":"10.0.17763.0","status":"affected","lessThan":"10.0.17763.8276","versionType":"custom"}],"platforms":["32-bit Systems","x64-based Systems"]},{"vendor":"Microsoft","product":"Windows 10 Version 21H2","versions":[{"version":"10.0.19044.0","status":"affected","lessThan":"10.0.19044.6809","versionType":"custom"}],"platforms":["32-bit Systems","ARM64-based Systems","x64-based Systems"]},{"vendor":"Microsoft","product":"Windows 10 Version 22H2","versions":[{"version":"10.0.19045.0","status":"affected","lessThan":"10.0.19045.6809","versionType":"custom"}],"platforms":["32-bit Systems","ARM64-based Systems","x64-based Systems"]},{"vendor":"Microsoft","product":"Windows Server 2019","versions":[{"version":"10.0.17763.0","status":"affected","lessThan":"10.0.17763.8276","versionType":"custom"}],"platforms":["x64-based Systems"]},{"vendor":"Microsoft","product":"Windows Server 2019 (Server Core installation)","versions":[{"version":"10.0.17763.0","status":"affected","lessThan":"10.0.17763.8276","versionType":"custom"}],"platforms":["x64-based Systems"]}],"references":["https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20810"],"weaknesses":["CWE-590"],"ingestedAt":"2026-10-29T20:11:10.572Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/20xxx/CVE-2026-20810.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-20810","state":"PUBLISHED","datePublished":"2026-01-13T17:56:10.446Z","dateUpdated":"2026-07-30T20:46:28.241Z","assignerShortName":"microsoft","assignerOrgId":"f38d906d-7342-40ea-92c1-6c4a2c6478c8","dateReserved":"2025-12-03T05:54:20.372Z"},"containers":{"cna":{"title":"Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability","descriptions":[{"lang":"en-US","value":"Free of memory not on the heap in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally."}],"affected":[{"vendor":"Microsoft","product":"Windows 10 Version 1809","versions":[{"version":"10.0.17763.0","status":"affected","lessThan":"10.0.17763.8276","versionType":"custom"}],"platforms":["32-bit Systems","x64-based Systems"]},{"vendor":"Microsoft","product":"Windows 10 Version 21H2","versions":[{"version":"10.0.19044.0","status":"affected","lessThan":"10.0.19044.6809","versionType":"custom"}],"platforms":["32-bit Systems","ARM64-based Systems","x64-based Systems"]},{"vendor":"Microsoft","product":"Windows 10 Version 22H2","versions":[{"version":"10.0.19045.0","status":"affected","lessThan":"10.0.19045.6809","versionType":"custom"}],"platforms":["32-bit Systems","ARM64-based Systems","x64-based Systems"]},{"vendor":"Microsoft","product":"Windows Server 2019","versions":[{"version":"10.0.17763.0","status":"affected","lessThan":"10.0.17763.8276","versionType":"custom"}],"platforms":["x64-based Systems"]},{"vendor":"Microsoft","product":"Windows Server 2019 (Server Core installation)","versions":[{"version":"10.0.17763.0","status":"affected","lessThan":"10.0.17763.8276","versionType":"custom"}],"platforms":["x64-based Systems"]}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20810","name":"Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability","tags":["vendor-advisory","patch"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en-US","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","baseSeverity":"HIGH","baseScore":7.8,"vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-590","description":"CWE-590: Free of Memory not on the Heap","lang":"en-US","type":"CWE"}]}],"providerMetadata":{"shortName":"microsoft","orgId":"f38d906d-7342-40ea-92c1-6c4a2c6478c8","dateUpdated":"2026-07-30T20:46:28.241Z"},"datePublic":"2026-01-13T16:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*","versionStartIncluding":"10.0.17763.0","versionEndExcluding":"10.0.17763.8276"},{"vulnerable":true,"criteria":"cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*","versionStartIncluding":"10.0.17763.0","versionEndExcluding":"10.0.17763.8276"},{"vulnerable":true,"criteria":"cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*","versionStartIncluding":"10.0.17763.0","versionEndExcluding":"10.0.17763.8276"},{"vulnerable":true,"criteria":"cpe:2.3:o:microsoft:windows_10_21H2:*:*:*:*:*:*:x86:*","versionStartIncluding":"10.0.19044.0","versionEndExcluding":"10.0.19044.6809"},{"vulnerable":true,"criteria":"cpe:2.3:o:microsoft:windows_10_22H2:*:*:*:*:*:*:x64:*","versionStartIncluding":"10.0.19045.0","versionEndExcluding":"10.0.19045.6809"}]}]}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-20810","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-01-14T04:56:55.383331Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-02-26T15:04:39.569Z"}}]}}}