CVE-2026-20934
Published: 13 January 2026
Summary
CVE-2026-20934 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows 10 21H2. 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 16.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Accurate timestamps from internal clocks enable detection of race conditions by providing reliable event ordering in audit logs.
Coordination of concurrent security activities reduces the probability that shared resources will be accessed simultaneously without proper synchronization.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Race condition in Windows SMB Server directly enables local privilege escalation via network exploitation of a remote service component.
NVD Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.
Deeper analysisAI
CVE-2026-20934 is a race condition vulnerability (CWE-362) in the Windows SMB Server, stemming from concurrent execution using a shared resource with improper synchronization. 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 high severity due to its potential for significant impact across confidentiality, integrity, and availability.
An authorized attacker with low privileges (PR:L) can exploit this vulnerability over the network (AV:N), though it requires high attack complexity (AC:H) and no user interaction (UI:N). Successful exploitation enables privilege escalation, allowing the attacker to achieve high-impact outcomes on the targeted system.
Mitigation details are available in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20934.
Details
- CWE(s)