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"original": {"product": "Windows 11 Version 24H2", "source": "cna", "vendor": "Microsoft"}, "product": "windows_11_24h2", "vendor": "microsoft"}, {"configurations": [{"platform": ["arm64-based_systems", "x64-based_systems"], "status": "affected", "versions": {"scheme": "generic", "value": "[10.0.26200.0,10.0.26200.8246)"}}], "enrichment": {"confidence": 86.0, "confidence_source": "matching", "scores": [{"score": 86.0, "source": "matching"}]}, "original": {"product": "Windows 11 Version 25H2", "source": "cna", "vendor": "Microsoft"}, "product": "windows_11_25h2", "vendor": "microsoft"}, {"configurations": [{"platform": ["x64-based_systems"], "status": "affected", "versions": {"scheme": "generic", "value": "[6.2.9200.0,6.2.9200.26026)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Windows Server 2012", "source": "cna", "vendor": "Microsoft"}, "product": "windows_server_2012", "vendor": "microsoft"}, {"configurations": [{"platform": ["x64-based_systems"], "status": "affected", "versions": {"scheme": "generic", "value": "[6.2.9200.0,6.2.9200.26026)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Windows Server 2012 (Server Core installation)", "source": "cna", "vendor": "Microsoft"}, "product": "windows_server_2012_(server_core_installation)", "vendor": "microsoft"}, {"configurations": [{"platform": ["x64-based_systems"], "status": "affected", "versions": {"scheme": "generic", "value": "[6.3.9600.0,6.3.9600.23132)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Windows Server 2012 R2", "source": "cna", "vendor": "Microsoft"}, "product": "windows_server_2012_r2", "vendor": "microsoft"}, {"configurations": [{"platform": ["x64-based_systems"], "status": 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"enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Windows Server 2016 (Server Core installation)", "source": "cna", "vendor": "Microsoft"}, "product": "windows_server_2016_(server_core_installation)", "vendor": "microsoft"}, {"configurations": [{"platform": ["x64-based_systems"], "status": "affected", "versions": {"scheme": "generic", "value": "[10.0.17763.0,10.0.17763.8644)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Windows Server 2019", "source": "cna", "vendor": "Microsoft"}, "product": "windows_server_2019", "vendor": "microsoft"}, {"configurations": [{"platform": ["x64-based_systems"], "status": "affected", "versions": {"scheme": "generic", "value": "[10.0.17763.0,10.0.17763.8644)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Windows Server 2019 (Server Core installation)", "source": "cna", "vendor": "Microsoft"}, "product": "windows_server_2019_(server_core_installation)", "vendor": "microsoft"}, {"configurations": [{"platform": ["x64-based_systems"], "status": "affected", "versions": {"scheme": "generic", "value": "[10.0.20348.0,10.0.20348.5020)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Windows Server 2022", "source": "cna", "vendor": "Microsoft"}, "product": "windows_server_2022", "vendor": "microsoft"}, {"configurations": [{"platform": ["x64-based_systems"], "status": "affected", "versions": {"scheme": "generic", "value": "[10.0.25398.0,10.0.25398.2274)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Windows Server 2022, 23H2 Edition (Server Core installation)", "source": "cna", "vendor": "Microsoft"}, "product": "windows_server_2022,_23h2_edition_(server_core_installation)", "vendor": "microsoft"}], "analysis": {"en": {"generated_at": "2026-04-14T19:42:30.556620+00:00", "value": {"mitigation_remediation": ["Install the Microsoft security update included in the latest cumulative update for Windows to address CVE\u20112026\u201133099.", "Verify that the update has been applied by checking the installed update history or using the Microsoft Update Catalog.", "Restrict execution of untrusted applications to non\u2011privileged accounts and enforce the principle of least privilege.", "If immediate patching is not possible, limit the installation of third\u2011party network services that rely on the Ancillary Function Driver to protected network segments and monitor for anomalous elevation attempts."], "summary": {"action": "Patch Immediately", "impact": "Privilege Escalation"}, "threat_synthesis": {"affected_systems": "Microsoft Windows\u00a010 versions 1607, 1809, 21H2, and 22H2; Windows\u00a011 versions 22H3, 23H2, 24H2, and 25H2; Windows\u00a0Server\u00a02012, Server\u00a02012\u00a0R2, Server\u00a02016, Server\u00a02019, Server\u00a02022, and Server\u00a023H2 (including core installations). All affected releases use the same ancillary driver module that contains the faulty use\u2011after\u2011free code.", "description_and_impact": "The vulnerability is a use\u2011after\u2011free condition in the Windows Ancillary Function Driver for WinSock. An attacker who can run code with user privileges can trigger the flaw and cause the driver to execute code with elevated rights. The flaw can let a local user gain higher\u2011privilege access, enabling installation of malware, modification of system settings, or other privileged actions. It corresponds to a classic memory\u2011management weakness mapped to CWE\u2011416.", "risk_and_exploitability": "The CVSS\u00a0v3.1 score is 7.0, indicating high severity for a local privilege\u2011escalation flaw. The EPSS score is not published, so the exact likelihood of exploitation is uncertain, but the flaw does not require network access and can be triggered by any application that runs as a user on the machine. The vulnerability is not in the CISA KEV catalog, suggesting no widespread weaponized exploits yet. An attacker with local access could therefore exploit the flaw to gain administrative rights, making the risk significant for systems that allow untrusted applications on the host."}}}}, "created": "2026-04-15T14:41:09.786910+00:00", "updated": "2026-04-15T15:15:06.484159+00:00", "vendors": ["microsoft", "microsoft$PRODUCT$windows_10_1607", "microsoft$PRODUCT$windows_10_1809", "microsoft$PRODUCT$windows_10_21h2", "microsoft$PRODUCT$windows_10_22h2", "microsoft$PRODUCT$windows_11_22h3", "microsoft$PRODUCT$windows_11_23h2", "microsoft$PRODUCT$windows_11_24h2", "microsoft$PRODUCT$windows_11_25h2", "microsoft$PRODUCT$windows_server_2012", "microsoft$PRODUCT$windows_server_2012_(server_core_installation)", "microsoft$PRODUCT$windows_server_2012_r2", "microsoft$PRODUCT$windows_server_2012_r2_(server_core_installation)", "microsoft$PRODUCT$windows_server_2016", "microsoft$PRODUCT$windows_server_2016_(server_core_installation)", "microsoft$PRODUCT$windows_server_2019", "microsoft$PRODUCT$windows_server_2019_(server_core_installation)", "microsoft$PRODUCT$windows_server_2022", "microsoft$PRODUCT$windows_server_2022,_23h2_edition_(server_core_installation)"]}