CVE-2026-20854

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{"analysis": {"en": {"generated_at": "2026-04-16T18:13:27.756898+00:00", "value": {"mitigation_remediation": ["Apply the latest Microsoft security update for CVE\u20112026\u201120854 via Windows Update or the Microsoft Update Catalog.", "Configure network firewall rules to allow inbound traffic to the LSASS process only from trusted hosts within the organization\u2019s perimeter.", "Enable Windows Defender Exploit Guard or AppLocker to restrict LSASS execution to approved binaries and prevent abuse of the vulnerable component."], "summary": {"action": "Immediate Patch", "impact": "Remote Code Execution"}, "threat_synthesis": {"affected_systems": "Microsoft products affected are Windows 11 24H2 and 25H2, as well as Windows Server 2025 and its Server Core installation. The vulnerability applies to all builds of these versions that have not yet applied the Microsoft security update referenced in the official advisory.", "description_and_impact": "This vulnerability is a use\u2011after\u2011free flaw in the Windows Local Security Authority Subsystem Service (LSASS). An attacker who can obtain an authorized session is able to craft a payload that causes LSASS to execute arbitrary code through the network. The resulting impact is the complete compromise of the system\u2019s confidentiality, integrity, and availability, as the attacker can run commands with LSASS privileges. The weakness is characterized by CWE\u2011416, indicating a use\u2011after\u2011free condition.", "risk_and_exploitability": "The vulnerability carries a CVSS score of 7.5, indicating high severity, but the EPSS score is below 1%, suggesting that exploitation attempts are currently unlikely. It is not listed in CISA\u2019s KEV catalog. The likely attack vector requires the attacker to obtain some authorized access to the target machine, after which the use\u2011after\u2011free flaw can be triggered over a network connection to execute arbitrary code with LSASS privileges. This remote code execution threat can compromise confidentiality, integrity, and availability of the system."}}}}, "created": "2026-04-16T18:15:43.300616+00:00", "updated": "2026-04-16T18:15:43.300627+00:00", "vendors": []}