CVE-2026-27909
Published: 14 April 2026
Summary
CVE-2026-27909 is a high-severity Use After Free (CWE-416) 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 20.3th 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 correction of the use-after-free flaw via vendor patches, directly eliminating the vulnerability.
Implements memory protection mechanisms like ASLR, DEP, and CFG that directly mitigate use-after-free exploits by preventing unauthorized memory access and code execution.
Enforces least privilege to restrict low-privileged local accounts from accessing resources necessary to trigger the privilege escalation vulnerability.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Use-after-free in Windows Search directly enables local privilege escalation from low to high privileges (T1068: Exploitation for Privilege Escalation).
NVD Description
Use after free in Microsoft Windows Search Component allows an authorized attacker to elevate privileges locally.
Deeper analysisAI
CVE-2026-27909 is a use-after-free vulnerability (CWE-416) in the Microsoft Windows Search Component. It affects Microsoft Windows systems and was published on 2026-04-14 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).
A local attacker with low privileges can exploit this vulnerability due to its low attack complexity and lack of required user interaction. Successful exploitation allows privilege escalation, granting high-impact access to confidentiality, integrity, and availability, potentially enabling full system compromise from an initial low-privilege position.
Microsoft's Security Response Center provides an update guide for mitigation at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-27909.
Details
- CWE(s)