CVE-2026-21513: MSHTML Framework Security Feature Bypass Vulnerability

Overview

Severity
High (CVSS 8.8)
CVSS Vector
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
Category
Security Feature Bypass
Exploit Status
Actively Exploited
Exploitation Likelihood
Detected
Publicly Disclosed
Yes
Patch Tuesday
2026-Feb
Released
2026-02-10
EPSS Score
27.97% (percentile: 96.5%)
CISA KEV
Listed — due 2026-03-03

Description

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

FAQ

According to the CVSS metric, the attack vector is user interaction is required (UI:R). How could an attacker exploit this security feature bypass vulnerability? An attacker could exploit this vulnerability by convincing a user to open a malicious HTML file or shortcut (.lnk) file delivered through a link, email attachment, or download. The specially crafted file manipulates browser and Windows Shell handling, causing the content to be executed by the operating system. This allows the attacker to bypass security features and potentially achieve code execution. What kind of security feature could be bypassed by successfully exploiting this vulnerability? This update address a vulnerability that bypasses prompts when executing a file.

Affected Products (31)

Windows

  • Windows 11 Version 26H1 for ARM64-based Systems
  • Windows 11 version 26H1 for x64-based Systems
  • Windows 10 Version 1809 for 32-bit Systems
  • Windows Server 2022
  • Windows Server 2022 (Server Core installation)
  • Windows Server 2019
  • Windows Server 2019 (Server Core installation)
  • Windows 10 Version 21H2 for ARM64-based Systems
  • Windows 10 Version 21H2 for x64-based Systems
  • Windows 10 Version 21H2 for 32-bit Systems
  • Windows Server 2025 (Server Core installation)
  • Windows 11 Version 25H2 for ARM64-based Systems
  • Windows 11 Version 23H2 for ARM64-based Systems
  • Windows 11 Version 25H2 for x64-based Systems
  • Windows 11 Version 23H2 for x64-based Systems
  • Windows Server 2022, 23H2 Edition (Server Core installation)
  • Windows 11 Version 24H2 for ARM64-based Systems
  • Windows 11 Version 24H2 for x64-based Systems
  • Windows Server 2025
  • Windows Server 2016
  • Windows 10 Version 1607 for 32-bit Systems
  • Windows Server 2016 (Server Core installation)
  • Windows 10 Version 1607 for x64-based Systems
  • Windows 10 Version 1809 for x64-based Systems

ESU

  • Windows 10 Version 22H2 for x64-based Systems
  • Windows 10 Version 22H2 for ARM64-based Systems
  • Windows 10 Version 22H2 for 32-bit Systems
  • Windows Server 2012
  • Windows Server 2012 R2
  • Windows Server 2012 (Server Core installation)
  • Windows Server 2012 R2 (Server Core installation)

Security Updates (14)

Acknowledgments

Google Threat Intelligence Group, Microsoft Threat Intelligence Center (MSTIC), Microsoft Security Response Center (MSRC), and Office Product Group Security Team

Revision History

  • 2026-02-10: Information published.