CVE-2026-20870
Published: 13 January 2026
Summary
CVE-2026-20870 is a high-severity Use After Free (CWE-416) vulnerability in Microsoft Windows 11 24H2. 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-16 (Memory Protection) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Requires identification, reporting, and timely patching of the use-after-free flaw in Windows Win32K ICOMP to prevent local privilege escalation.
Implements memory safeguards such as DEP, ASLR, and stack canaries to protect against exploitation of use-after-free vulnerabilities in kernel components.
Enforces least privilege for local accounts, limiting the attack surface and potential damage from low-privilege escalation attempts via the vulnerability.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Use-after-free in Win32K kernel component 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-2026-20870 is a use-after-free vulnerability (CWE-416) in the Windows Win32K ICOMP component. It affects Windows systems and was published on 2026-01-13T18:16:16.650 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).
The vulnerability allows an authorized local attacker with low privileges to elevate privileges. Exploitation requires local access and low complexity with no user interaction, enabling high impacts on confidentiality, integrity, and availability.
Microsoft's Security Response Center has published an update guide for this vulnerability at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20870, which provides details on associated patches and mitigation recommendations.
Details
- CWE(s)