Is CVE-2026-21519 being actively exploited?

Yes. CVE-2026-21519 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added on February 10, 2026.

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

CVE-2026-21519 has a CVSS 3.1 base score of 7.8 (HIGH).

CVE-2026-21519

HIGH · CVSS 7.8CISA KEV: actively exploitedEPSS 2.5%EU EUVD: exploited

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

Key facts

CVSS score: 7.8 (v3.1)
Severity: HIGH
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-843
EPSS score: 2.5% (84th percentile)
In CISA KEV: Yes, added February 10, 2026
In EU EUVD: Yes (EUVD-2026-7358)
Published: February 10, 2026
NVD last modified: June 17, 2026
Status: Analyzed

CISA Known Exploited Vulnerability

Microsoft Windows Type Confusion Vulnerability

Added to the KEV catalog on February 10, 2026; federal remediation due March 3, 2026.

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2026-7358 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on August 19, 2026.

View on the EU Vulnerability Database

Affected products

microsoft / windows 10 1607
microsoft / windows 10 1607
microsoft / windows 10 1809
microsoft / windows 10 1809
microsoft / windows 10 21h2
microsoft / windows 10 21h2
microsoft / windows 10 21h2
microsoft / windows 10 22h2
microsoft / windows 10 22h2
microsoft / windows 10 22h2
microsoft / windows 11 23h2
microsoft / windows 11 23h2
microsoft / windows 11 24h2
microsoft / windows 11 24h2
microsoft / windows 11 25h2
microsoft / windows 11 25h2
microsoft / windows server 2016
microsoft / windows server 2019
microsoft / windows server 2022
microsoft / windows server 2022 23h2
microsoft / windows server 2025

Certified products that may be affected

1 FIPS 140 or Common Criteria certified product, from automated matching by sec-certs.org.

Microsoft Windows 10 and Server version 1903 (May 2019 Update) - Microsoft Corporation - Common Criteria 2019-22-INF-2839 - archived

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21519(Vendor Advisory)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21519(US Government Resource)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

Query CVEs from your AI assistant

The CVE/NVD Explorer brain answers CVE questions directly inside Claude, ChatGPT, or any MCP assistant — always up to date, no setup. Add it once and stop pasting advisories into chat.

Add the CVE brain