What is CVE-2025-53809?

CVE-2025-53809 is a medium-severity vulnerability in Microsoft Windows_11_24h2, classified under Improper Input Validation. CVSS score: 6.5/10. Published 2025-09-09.

How severe is CVE-2025-53809?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Improper input validation in Microsoft Windows_11_24h2

CVE-2025-53809

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

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.014 (68.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Microsoft Windows_11_24h2
Microsoft Windows 11 Version 24h2 — versions 10.0.26100.0
Microsoft Windows Server 2025 — versions 10.0.26100.0
Microsoft Windows_server_2025
Microsoft Windows Server 2025 (Server Core Installation) — versions 10.0.26100.0

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

secure@microsoft.com (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2025-53809?: CVE-2025-53809 is a medium-severity vulnerability in Microsoft Windows_11_24h2, classified under Improper Input Validation. CVSS score: 6.5/10. Published 2025-09-09.
How severe is CVE-2025-53809?: Medium severity. CVSS v3 base score is 6.5 out of 10.