FalehSec Exploited-vulnerability triage · joined from CISA KEV, NVD CVSS and EPSS

CVE-2026-21519

Microsoft · Windows · Microsoft Windows Type Confusion Vulnerability

Verdict
Patch on your normal cycle · actively exploited, not reachable unauthenticated from the internet, and in the top 25% of CVEs by near-term exploitation probability

Added to CISA KEV 2026-02-10 · exploited in the wild for 229 days

What an attacker can reach How likely Time What CISA says to do Sources All 545

What an attacker can reach

CVSS 7.8 HIGH. The score is a summary; these three components are the part that decides whether something scanning the internet can use it.

Attack vectorlocalrequires local access to the machine
Privileges requiredlowneeds some credentials, so a fully anonymous attacker cannot reach it directly
User interactionnonecan be triggered with nobody interacting with the page or request
Base vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
WeaknessCWE-843

This describes the vulnerability. It says nothing about whether your systems run it.

How likely

EPSS puts the probability of exploitation in the next 30 days at 0.0246, which places it in the top 25% of all tracked CVEs. The percentile is the more useful half: 0.18 in absolute terms sounds low until you know most of the internet-facing software in the world scores under that.

EPSS probability0.0246
Percentile0.838 — top 25%

Time

Added to KEV2026-02-10
Days exploited229
Federal remediation duenot set
Ransomware useno known ransomware campaign use

What CISA says to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

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

Sources