What is the CVSS score of CVE-2026-21519?

CVE-2026-21519 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 3.1%.

Which versions of Windows 10 1607 are affected by CVE-2026-21519?

CVE-2026-21519 is a high-severity Windows vulnerability actively exploited in the wild that allows authenticated users to gain SYSTEM-level access to affected systems.. A patch is available.

Is CVE-2026-21519 being actively exploited?

Yes, CVE-2026-21519 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild exploitation. Immediate patching is required.

How to fix or mitigate CVE-2026-21519?

Within 24 hours: Inventory all Windows systems running affected DWM versions and assess exposure in high-value environments (domain controllers, servers, sensitive workstations). Within 7 days: Implement compensating controls including strict user access policies, disable unnecessary local login capabilities, and enforce application whitelisting where feasible. Within 30 days: Maintain continuous vendor monitoring for patch availability and prepare expedited deployment procedures; escalate to Windows/Microsoft stakeholders to request hotfix timelines.

Windows 10 1607 CVE-2026-21519

HIGH

Access of Resource Using Incompatible Type (Type Confusion) (CWE-843)

2026-02-10 secure@microsoft.com

Buffer Overflow Microsoft Windows 10 1607 Windows 10 1809 Windows 10 21h2 Windows 10 22h2 Windows 11 23h2 Windows 11 24h2 Windows 11 25h2 Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows Server 2022 23h2 Windows Server 2025

7.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.8 HIGH

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:02 vuln.today

Added to CISA KEV

Feb 11, 2026 - 16:13 cisa

CISA KEV

CVE Published

Feb 10, 2026 - 18:16 nvd

HIGH 7.8

DescriptionCVE.org

Access of resource using incompatible type ('type confusion') in Desktop Window Manager allows an authorized attacker to elevate privileges locally.

AnalysisAI

Desktop Window Manager (DWM) in Windows contains a type confusion vulnerability (CVE-2026-21519, CVSS 7.8) that enables authorized local attackers to escalate privileges. KEV-listed, this kernel-level vulnerability in the Windows compositor allows any authenticated user to achieve SYSTEM-level access through exploitation of an incompatible type access in DWM's resource handling.

Technical ContextAI

DWM is the Windows desktop compositor running as a SYSTEM-level service. The type confusion occurs when DWM accesses an internal resource using an incompatible type, causing the data to be misinterpreted. Because DWM runs with SYSTEM privileges and handles rendering for all desktop applications, exploiting this vulnerability grants complete system control. DWM vulnerabilities are valuable post-compromise tools.

RemediationAI

Apply Microsoft security update. Monitor for suspicious DWM interactions. Implement least-privilege access to limit impact of privilege escalation. Use endpoint detection for post-exploitation behaviors.