Summary
Impact: Denial of Service. Microsoft rating: Important. Not known to be exploited — Exploitation Unlikely. Customer action: Required.
Details
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation of this vulnerability requires an attacker to invest time in repeated exploitation attempts through sending constant or intermittent data.
What actions do I need to take to be protected from this vulnerability?
To mitigate this vulnerability, a code change was made in the July 2025 Windows Security Updates for all other Server platforms from Windows Server 2008 SP2 to Windows Server 2022, inclusive.
After this change, some file and print service software can be affected, including Samba. Samba has released an update to accommodate this change. See Samba 4.22.3 - Release Notes for more information.
To accommodate scenarios where affected third party software cannot be updated, we released additional configuration capability in the August 2025 Windows Security Update.
For more information about the releases and the new modes visit: https://support.microsoft.com/en-us/topic/kb5066014-netlogon-rpc-hardening-cve-2025-49716-38a0bc06-507c-47d4-be0f-ca1acab02c68
Security updates
10.0.17763.7558 — https://support.microsoft.com/help/5062557
10.0.20348.3932 — https://support.microsoft.com/help/5062572
10.0.25398.1732 — https://support.microsoft.com/help/5062570
10.0.14393.8246 — https://support.microsoft.com/help/5062560
6.0.6003.23418 — https://support.microsoft.com/help/5062624
6.0.6003.23418 — https://support.microsoft.com/help/5062618
6.1.7601.27820 — https://support.microsoft.com/help/5062632
6.1.7601.27820 — https://support.microsoft.com/help/5062619
6.2.9200.25573 — https://support.microsoft.com/help/5062592
6.3.9600.22676 — https://support.microsoft.com/help/5062597
Vulnerabilities 1
-
High 7.5
Windows Netlogon Denial of Service Vulnerability
Uncontrolled resource consumption in Windows Netlogon allows an unauthorized attacker to deny service over a network.
Revision history
-
#2
Updated first FAQ to state that CVE-2020-0674 has now been issued to address this vulnerability. This is an informational change only.
-
#1
Information published.
References
-
CVE-2025-49716 Windows Netlogon Denial of Service Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-49716
-
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
-
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
-
Common Vulnerability Scoring System
https://www.first.org/cvss