CVE-2026-21513 kev in the critical feed json
MSHTML Framework Security Feature Bypass Vulnerability
published 2026-02-10 8 mo ago modified 2026-08-19 2 mo ago also EUVD-2026-7342
- cvss
- 8.8
- version 3.1, CNA
- cisa kev
- Exploited
- added 2026-02-10
- epss
- 15.9%
- EPSS 15.9% chance of exploitation in 30 days, percentile 96%
- public exploits
- 0
- none known
Summary
Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.
Patch / fix
cisa required action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Microsoft Windows 10 Version 1607 10.0.14393.8868
- Microsoft Windows 10 Version 1809 10.0.17763.8389
- Microsoft Windows 10 Version 21H2 10.0.19044.6937
- Microsoft Windows 10 Version 22H2 10.0.19045.6937
- Microsoft Windows 11 version 22H3 10.0.22631.6649
- Microsoft Windows 11 Version 23H2 10.0.22631.6649
- Microsoft Windows 11 Version 24H2 10.0.26100.7840
- Microsoft Windows 11 Version 25H2 10.0.26200.7840
- Microsoft Windows 11 version 26H1 10.0.28000.1575
- Microsoft Windows Server 2012 6.2.9200.25923
- Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.25923
- Microsoft Windows Server 2012 R2 6.3.9600.23022
- Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.23022
- Microsoft Windows Server 2016 10.0.14393.8868
- Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.8868
- Microsoft Windows Server 2019 10.0.17763.8389
- Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.8389
- Microsoft Windows Server 2022 10.0.20348.4773
- Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2149
- Microsoft Windows Server 2025 10.0.26100.32370
- Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.32370
Timeline
- 0-day patched (Project Zero)
- Added to CISA KEV
- Published
- CISA SSVC: exploitation active
- CISA patch deadline
Known exploited
- Added
- 8 mo ago
- Patch by
- 2026-03-03 (8 mo ago)
- Ransomware
- Not known
- Required action
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Vendor, product
- Microsoft, Windows
- CISA name
- Microsoft MSHTML Framework Protection Mechanism Failure Vulnerability
Zero-day
Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.
- Patched
- 2026-02-10
- Details
- project zero tracker
CISA SSVC
- Exploitation
- Active, exploited in the wild
- Automatable
- no
- Technical impact
- total
- Assessed
- 8 mo ago
Exploit prediction
15.85% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C |
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
Affected products
- Microsoft Windows 10 Version 1607
- Microsoft Windows 10 Version 1809
- Microsoft Windows 10 Version 21H2
- Microsoft Windows 10 Version 22H2
- Microsoft Windows 11 version 22H3
- Microsoft Windows 11 Version 23H2
- Microsoft Windows 11 Version 24H2
- Microsoft Windows 11 Version 25H2
- Microsoft Windows 11 version 26H1
- Microsoft Windows Server 2012
- Microsoft Windows Server 2012 (Server Core installation)
- Microsoft Windows Server 2012 R2
- Microsoft Windows Server 2012 R2 (Server Core installation)
- Microsoft Windows Server 2016
- Microsoft Windows Server 2016 (Server Core installation)
- Microsoft Windows Server 2019
- Microsoft Windows Server 2019 (Server Core installation)
- Microsoft Windows Server 2022
- Microsoft Windows Server 2022, 23H2 Edition (Server Core installation)
- Microsoft Windows Server 2025
- Microsoft Windows Server 2025 (Server Core installation)
Classification
- Weakness
-
- CWE-693 Protection Mechanism Failure
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2026-21513
vendor-advisory, patch
-
cisa.gov
/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21513
government-resource, us-government-resource
-
vicarius.io
/vsociety/posts/cve-2026-21513-detection-script-security-feature-bypass-vulnerability-in-mshtml-framework
third-party-advisory
-
vicarius.io
/vsociety/posts/cve-2026-21513-mitigation-script-security-feature-bypass-vulnerability-in-mshtml-framework
mitigation, third-party-advisory
Sources
- CVE List CVE-2026-21513
- NVD CVE-2026-21513
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.