CVE-2025-53809

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

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

1.6% chance of exploitation in the next 30 days; higher than 75% of CVEs (scores of 2026-10-25)

CWE

CWE-20

Published

2025-09-09

Modified

2026-10-18

Record from

the NVD, synced 2026-10-19

Affected

• microsoft:windows_11_24h2
• microsoft:windows_server_2025

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53809

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