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CVE-2026-21513

MSHTML Framework Security Feature Bypass Vulnerability

  • High 8.8
  • Exploited: added to CISA KEV 10 Feb 2026

Description

Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.

Key facts

Published
10 Feb 2026
Last changed
19 Aug 2026
Assigned by
microsoft
KEV added
10 Feb 2026
KEV fix due
3 Mar 2026
EPSS
15.852% likely to be exploited in the next 30 days, higher than 96.934% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: no; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 8.8CVSS 3.1, Highfrom the CNA (microsoft)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

What 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.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
MicrosoftWindows 10 Version 1607
  • 10.0.14393.0 up to but excluding 10.0.14393.8868 (affected)
MicrosoftWindows 10 Version 1809
  • 10.0.17763.0 up to but excluding 10.0.17763.8389 (affected)
MicrosoftWindows 10 Version 21H2
  • 10.0.19044.0 up to but excluding 10.0.19044.6937 (affected)
MicrosoftWindows 10 Version 22H2
  • 10.0.19045.0 up to but excluding 10.0.19045.6937 (affected)
MicrosoftWindows 11 version 22H3
  • 10.0.22631.0 up to but excluding 10.0.22631.6649 (affected)
MicrosoftWindows 11 Version 23H2
  • 10.0.22631.0 up to but excluding 10.0.22631.6649 (affected)
MicrosoftWindows 11 Version 24H2
  • 10.0.26100.0 up to but excluding 10.0.26100.7840 (affected)
MicrosoftWindows 11 Version 25H2
  • 10.0.26200.0 up to but excluding 10.0.26200.7840 (affected)
MicrosoftWindows 11 version 26H1
  • 10.0.28000.0 up to but excluding 10.0.28000.1575 (affected)
MicrosoftWindows 11 Version 26H1
  • 10.0.28000.0 up to but excluding 10.0.28000.1575 (affected)
MicrosoftWindows Server 2012
  • 6.2.9200.0 up to but excluding 6.2.9200.25923 (affected)
MicrosoftWindows Server 2012 (Server Core installation)
  • 6.2.9200.0 up to but excluding 6.2.9200.25923 (affected)
MicrosoftWindows Server 2012 R2
  • 6.3.9600.0 up to but excluding 6.3.9600.23022 (affected)
MicrosoftWindows Server 2012 R2 (Server Core installation)
  • 6.3.9600.0 up to but excluding 6.3.9600.23022 (affected)
MicrosoftWindows Server 2016
  • 10.0.14393.0 up to but excluding 10.0.14393.8868 (affected)
MicrosoftWindows Server 2016 (Server Core installation)
  • 10.0.14393.0 up to but excluding 10.0.14393.8868 (affected)
MicrosoftWindows Server 2019
  • 10.0.17763.0 up to but excluding 10.0.17763.8389 (affected)
MicrosoftWindows Server 2019 (Server Core installation)
  • 10.0.17763.0 up to but excluding 10.0.17763.8389 (affected)
MicrosoftWindows Server 2022
  • 10.0.20348.0 up to but excluding 10.0.20348.4773 (affected)
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)
  • 10.0.25398.0 up to but excluding 10.0.25398.2149 (affected)
MicrosoftWindows Server 2025
  • 10.0.26100.0 up to but excluding 10.0.26100.32370 (affected)
MicrosoftWindows Server 2025 (Server Core installation)
  • 10.0.26100.0 up to but excluding 10.0.26100.32370 (affected)

Timeline

  1. 10 Feb 2026 CVE-2026-21513 added to CISA KEV
  2. 10 Feb 2026 Added to the CISA KEV catalogue
  3. 10 Feb 2026 Published

Weakness

References