CVE-2026-20920
Published: 13 January 2026
Summary
CVE-2026-20920 is a high-severity Use After Free (CWE-416) vulnerability in Microsoft Windows 11 23H2. 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 10.2th 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).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly remediates the use-after-free vulnerability in Windows Win32K ICOMP by identifying, testing, and applying vendor patches in a timely manner.
Provides memory protection mechanisms like address space layout randomization and data execution prevention that mitigate exploitation of use-after-free flaws in kernel subsystems.
Limits the privileges of local low-privilege accounts and processes, reducing the attack surface and impact of privilege escalation via Win32K exploitation.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Kernel use-after-free in Win32K directly enables local privilege escalation from low-privileged context (T1068).
NVD Description
Use after free in Windows Win32K - ICOMP allows an authorized attacker to elevate privileges locally.
Deeper analysisAI
CVE-2026-20920 is a use-after-free vulnerability (CWE-416) in the Windows Win32K ICOMP component, published on 2026-01-13 with a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). It affects the Windows kernel's Win32K subsystem, which handles graphical user interface operations and input processing.
A local attacker with low privileges can exploit this vulnerability with low complexity and no user interaction required. Successful exploitation allows privilege escalation, potentially granting the attacker high-impact access to confidentiality, integrity, and availability of system resources.
Microsoft's security advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20920 provides details on available patches and recommended mitigations.
Details
- CWE(s)