What is CVE-2025-53809?

CVE-2025-53809 is a security advisory published by Microsoft Security Response Center (MSRC) with High severity. Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability

Which CVE IDs does CVE-2025-53809 cover?

CVE-2025-53809 covers the following CVE IDs: CVE-2025-53809. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2025-53809?

CVE-2025-53809 has a CVSS v3 base score of 6.5, published by Microsoft Security Response Center (MSRC).

Which products are affected by CVE-2025-53809?

CVE-2025-53809 affects 4 products, including: Windows 11 Version 24H2 for ARM64-based Systems; Windows 11 Version 24H2 for x64-based Systems; Windows Server 2025; Windows Server 2025 (Server Core installation).

CVE-2025-53809HighCVSS 6.5

Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability

Vendor

Microsoft Security Response Center (MSRC)

Published

June 3, 2026

Last Modified

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🔗 CVE IDs covered (1)

CVE-2025-53809 →

📋 Description

Improper input validation in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to deny service over a network.

🎯 Affected products4

Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows Server 2025
Windows Server 2025 (Server Core installation)

✅ Remediation

KB5065426 (Security Update) — fixed build 10.0.26100.6584 KB5065474 (SecurityHotpatchUpdate) — fixed build 10.0.26100.6508 KB5065474 (Security Hotpatch Update) — fixed build 10.0.26100.6508

🔗 References (5)

advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53809
patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5065426
referencehttps://support.microsoft.com/help/5065426
patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5065474
referencehttps://support.microsoft.com/help/5065474