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CVE-2026-20927

Windows SMB Server Denial of Service Vulnerability

Published: Jan 13, 2026Updated: Jan 16, 2026 Sources: CVE List NVD BDUCWE-362
5.3MEDIUM
NVD MITRE
EPSS Score
0.9%
Top 45.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to deny service over a network.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:LUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-362

Affected Products

Microsoft Corp
commercial·USaka Microsoft, microsoft corporation
Windows Server 2025 (Server Core installation)On-premOS
Operating Systems / windows
Windows 11 version 22H3On-premOS
Operating Systems / windows
Windows Server 2022, 23H2 Edition (Server Core installation)On-premOS
Operating Systems / windows
Windows 10 Version 1607On-premOS
Operating Systems / windows
Windows Server 2019 (Server Core installation)On-premOS
Operating Systems / windows
Windows Server 2012 R2 (Server Core installation)On-premOS
Operating Systems / windows
Windows Server 2012 (Server Core installation)On-premOS
Operating Systems / windows
Windows Server 2008 R2 Service Pack 1 (Server Core installation)On-premOS
Operating Systems / windows
and 54 more affected products View all →

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-20927?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique
Privilege Escalation
View detailed technique mapping

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20927
msrc.microsoft.com
News mentions
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