CVE-2026-20919
Published: 13 January 2026
Summary
CVE-2026-20919 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows 10 1607. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 9.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and AC-6 (Least Privilege).
Deeper analysis
CVE-2026-20919 is a race condition vulnerability (CWE-362) stemming from concurrent execution using a shared resource with improper synchronization in the Windows SMB Server. Published on 2026-01-13, it carries a CVSS v3.1 base score of 7.5 (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating network accessibility, high attack complexity, and significant impacts across confidentiality, integrity, and availability.
An authorized attacker with low privileges (PR:L) can exploit this vulnerability over the network without user interaction. Successful exploitation enables privilege escalation, allowing the attacker to achieve high-level impacts on the targeted system.
Microsoft's update guide provides details on mitigation for CVE-2026-20919 at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20919.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2136
Vulnerability details
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Race condition in Windows SMB Server directly enables local privilege escalation via network exploitation by low-privileged attackers.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Flaw remediation requires timely installation of the Microsoft patch that directly resolves the race condition vulnerability in the Windows SMB Server.
Least privilege restricts low-privilege authorized users from achieving full escalation impact via the SMB server race condition.
System monitoring identifies anomalous SMB network connections and privilege escalations signaling exploitation of the race condition.