Vulnerability Description
Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.
CVSS Score
8.8
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows 10 1607 | < 10.0.14393.8868 |
| Microsoft | Windows 10 1809 | < 10.0.17763.8389 |
| Microsoft | Windows 10 21H2 | < 10.0.19044.6937 |
| Microsoft | Windows 10 22H2 | < 10.0.19045.6937 |
| Microsoft | Windows 11 23H2 | < 10.0.22631.6649 |
| Microsoft | Windows 11 24H2 | < 10.0.26100.7781 |
| Microsoft | Windows 11 25H2 | < 10.0.26200.7781 |
| Microsoft | Windows Server 2012 | - |
| Microsoft | Windows Server 2016 | < 10.0.14393.8868 |
| Microsoft | Windows Server 2019 | < 10.0.17763.8389 |
| Microsoft | Windows Server 2022 | < 10.0.20348.4711 |
| Microsoft | Windows Server 2022 23H2 | < 10.0.25398.2149 |
| Microsoft | Windows Server 2025 | < 10.0.26100.32313 |
Related Weaknesses (CWE)
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21513Vendor Advisory
- https://www.vicarius.io/vsociety/posts/cve-2026-21513-detection-script-security-Third Party Advisory
- https://www.vicarius.io/vsociety/posts/cve-2026-21513-mitigation-script-securityMitigationThird Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-US Government Resource
FAQ
What is CVE-2026-21513?
CVE-2026-21513 is a vulnerability with a CVSS score of 8.8 (HIGH). Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.
How severe is CVE-2026-21513?
CVE-2026-21513 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-21513?
Check the references section above for vendor advisories and patch information. Affected products include: Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 21H2, Microsoft Windows 10 22H2, Microsoft Windows 11 23H2.