CVE-2026-20875 Microsoft CVE debrief

Who should care

System administrators and security professionals responsible for Windows systems, particularly those using affected versions of Windows 10, Windows 11, and Windows Server, should be aware of this vulnerability and take necessary mitigation steps.

Technical summary

The CVE-2026-20875 vulnerability is a null pointer dereference in the Windows Local Security Authority Subsystem Service (LSASS). This vulnerability allows an unauthorized attacker to deny service over a network. The Common Vulnerability Scoring System (CVSS) score for this vulnerability is 7.5, indicating a high severity level. Multiple versions of Windows are affected, including Windows 10, Windows 11, and various Windows Server versions.

Defensive priority

This vulnerability has a high CVSS score of 7.5 and is classified as HIGH severity. A null pointer dereference in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network. Immediate attention is required to assess and mitigate potential risks.

Recommended defensive actions

• Review and apply vendor advisories and patches for CVE-2026-20875
• Assess the vulnerability's impact on your environment and prioritize mitigation
• Monitor system logs for potential exploitation attempts
• Implement compensating controls to reduce the attack surface
• Verify and update affected Windows versions according to vendor guidance

Evidence notes

The CVE-2026-20875 record indicates a null pointer dereference vulnerability in Windows Local Security Authority Subsystem Service (LSASS), which could allow an unauthorized attacker to deny service over a network. The CVSS score is 7.5, classified as HIGH severity. The vulnerability affects multiple Windows versions and has been analyzed by the NVD.

Official resources