CVE-2026-27911
Published: 14 April 2026
Summary
CVE-2026-27911 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows 10 21H2. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 12.4th 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 SC-4 (Information in Shared System Resources) and SI-16 (Memory Protection).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Timely flaw remediation through vendor patches directly eliminates the race condition and use-after-free vulnerability in Windows User Interface Core, preventing local privilege escalation.
Memory protection mechanisms such as ASLR and DEP comprehensively mitigate exploitation of the use-after-free component (CWE-416) associated with this privilege escalation vulnerability.
Protection against unauthorized information transfer via shared system resources directly addresses the race condition (CWE-362) from improper synchronization in concurrent execution.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local privilege escalation via race condition/use-after-free in Windows UI Core directly enables T1068 (Exploitation for Privilege Escalation).
NVD Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows User Interface Core allows an authorized attacker to elevate privileges locally.
Deeper analysisAI
CVE-2026-27911 is a race condition vulnerability stemming from concurrent execution using a shared resource with improper synchronization (CWE-362), along with a use-after-free issue (CWE-416), in the Windows User Interface Core component. Published on 2026-04-14, it allows an authorized local attacker to elevate privileges. The vulnerability carries a CVSS v3.1 base score of 7.8 (AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H), indicating high severity due to its potential for significant impact despite local access requirements.
Exploitation requires local access and low privileges (PR:L), with high attack complexity (AC:H) but no user interaction (UI:N). A successful attack changes scope (S:C) and grants high impacts across confidentiality, integrity, and availability (C:H/I:H/A:H), enabling the attacker to escalate from low-privileged to higher-privileged execution on the affected Windows system.
Microsoft's Security Response Center (MSRC) update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-27911 provides details on patches and mitigation recommendations for this vulnerability.
Details
- CWE(s)