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 15.0th 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).
Deeper analysis
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.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-22451
Vulnerability details
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows User Interface Core allows an authorized attacker to elevate privileges locally.
- CWE(s)
Related Threats
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).
CVEs Like This One
Affected Assets
Mitigating Controls
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.