CVE-2025-53809 Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability
An authorized attacker can cause a denial of service in Windows LSASS via improper input validation, affecting Windows 11 and Server 2025.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-53809?
CVE-2025-53809 is a medium-severity denial of service vulnerability in Microsoft Windows 11 24h2, published on 9 Sep 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Improper input validation in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to deny service over a network.
Weakness: CWE-20
Which versions are affected by CVE-2025-53809?
It affects 2 products.
Products include Microsoft Windows 11 24h2, Microsoft Windows Server 2025.
How do I fix CVE-2025-53809?
No fix has been published for CVE-2025-53809 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-53809 being exploited?
There is no known exploitation of CVE-2025-53809 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows 11 24h2
- CVE-2025-60710 Microsoft Windows Link Following
- CVE-2026-54990 Remote Desktop Client Remote Code Execution Vulnerability
- CVE-2025-50165 Windows Graphics Component Remote Code Execution Vulnerability
- CVE-2025-21311 Windows NTLM V1 Elevation of Privilege Vulnerability
- CVE-2026-108463 Windows SmartScreen Security Feature Bypass Vulnerability
Sources
Also known as GHSA-45gp-pfc8-39m2.