MSHTML Framework Security Feature Bypass Vulnerability
Summary
| CVE | CVE-2026-21513 |
|---|---|
| State | PUBLISHED |
| Assigner | microsoft |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-02-10 18:16:33 UTC |
| Updated | 2026-03-30 13:28:07 UTC |
| Description | Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network. |
Risk And Classification
Primary CVSS: v3.1 8.8 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS: 0.279740000 probability, percentile 0.964350000 (date 2026-04-01)
CISA KEV: Listed on 2026-02-10; due 2026-03-03; ransomware use Unknown
Problem Types: CWE-693 | CWE-693 CWE-693: Protection Mechanism Failure
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 8.8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 8.8 | HIGH | 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 |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
RequiredScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CISA Known Exploited Vulnerability
| Vendor | Microsoft |
|---|---|
| Product | Windows |
| Name | Microsoft MSHTML Framework Protection Mechanism Failure Vulnerability |
| 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. |
| Notes | https://msrc.microsoft.com/update-guide/advisory/CVE-2026-21513 ; https://nvd.nist.gov/vuln/detail/CVE-2026-21513 |
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Operating System | Microsoft | Windows 10 1607 | All | All | All | All |
| Operating System | Microsoft | Windows 10 1607 | All | All | All | All |
| Operating System | Microsoft | Windows 10 1809 | All | All | All | All |
| Operating System | Microsoft | Windows 10 1809 | All | All | All | All |
| Operating System | Microsoft | Windows 10 21h2 | All | All | All | All |
| Operating System | Microsoft | Windows 10 21h2 | All | All | All | All |
| Operating System | Microsoft | Windows 10 21h2 | All | All | All | All |
| Operating System | Microsoft | Windows 10 22h2 | All | All | All | All |
| Operating System | Microsoft | Windows 10 22h2 | All | All | All | All |
| Operating System | Microsoft | Windows 10 22h2 | All | All | All | All |
| Operating System | Microsoft | Windows 11 23h2 | All | All | All | All |
| Operating System | Microsoft | Windows 11 23h2 | All | All | All | All |
| Operating System | Microsoft | Windows 11 24h2 | All | All | All | All |
| Operating System | Microsoft | Windows 11 24h2 | All | All | All | All |
| Operating System | Microsoft | Windows 11 25h2 | All | All | All | All |
| Operating System | Microsoft | Windows 11 25h2 | All | All | All | All |
| Operating System | Microsoft | Windows Server 2012 | - | All | All | All |
| Operating System | Microsoft | Windows Server 2012 | r2 | All | All | All |
| Operating System | Microsoft | Windows Server 2016 | All | All | All | All |
| Operating System | Microsoft | Windows Server 2019 | All | All | All | All |
| Operating System | Microsoft | Windows Server 2022 | All | All | All | All |
| Operating System | Microsoft | Windows Server 2022 23h2 | All | All | All | All |
| Operating System | Microsoft | Windows Server 2025 | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Microsoft | Windows 10 Version 1607 | affected 10.0.14393.0 10.0.14393.8868 custom | 32-bit Systems, x64-based Systems |
| CNA | Microsoft | Windows 10 Version 1809 | affected 10.0.17763.0 10.0.17763.8389 custom | 32-bit Systems, x64-based Systems |
| CNA | Microsoft | Windows 10 Version 21H2 | affected 10.0.19044.0 10.0.19044.6937 custom | 32-bit Systems, ARM64-based Systems, x64-based Systems |
| CNA | Microsoft | Windows 10 Version 22H2 | affected 10.0.19045.0 10.0.19045.6937 custom | 32-bit Systems, ARM64-based Systems, x64-based Systems |
| CNA | Microsoft | Windows 11 Version 22H3 | affected 10.0.22631.0 10.0.22631.6649 custom | ARM64-based Systems |
| CNA | Microsoft | Windows 11 Version 23H2 | affected 10.0.22631.0 10.0.22631.6649 custom | x64-based Systems |
| CNA | Microsoft | Windows 11 Version 24H2 | affected 10.0.26100.0 10.0.26100.7840 custom | ARM64-based Systems, x64-based Systems |
| CNA | Microsoft | Windows 11 Version 25H2 | affected 10.0.26200.0 10.0.26200.7840 custom | Not specified |
| CNA | Microsoft | Windows 11 Version 26H1 | affected 10.0.28000.0 10.0.28000.1575 custom | ARM64-based Systems |
| CNA | Microsoft | Windows 11 Version 26H1 | affected 10.0.28000.0 10.0.28000.1575 custom | Not specified |
| CNA | Microsoft | Windows Server 2012 | affected 6.2.9200.0 6.2.9200.25923 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2012 Server Core Installation | affected 6.2.9200.0 6.2.9200.25923 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2012 R2 | affected 6.3.9600.0 6.3.9600.23022 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2012 R2 Server Core Installation | affected 6.3.9600.0 6.3.9600.23022 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2016 | affected 10.0.14393.0 10.0.14393.8868 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2016 Server Core Installation | affected 10.0.14393.0 10.0.14393.8868 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2019 | affected 10.0.17763.0 10.0.17763.8389 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2019 Server Core Installation | affected 10.0.17763.0 10.0.17763.8389 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2022 | affected 10.0.20348.0 10.0.20348.4773 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2022 23H2 Edition Server Core Installation | affected 10.0.25398.0 10.0.25398.2149 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2025 | affected 10.0.26100.0 10.0.26100.32370 custom | x64-based Systems |
| CNA | Microsoft | Windows Server 2025 Server Core Installation | affected 10.0.26100.0 10.0.26100.32370 custom | x64-based Systems |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.vicarius.io/vsociety/posts/cve-2026-21513-detection-script-security-featu... | af854a3a-2127-422b-91ae-364da2661108 | www.vicarius.io | Third Party Advisory |
| www.vicarius.io/vsociety/posts/cve-2026-21513-mitigation-script-security-feat... | af854a3a-2127-422b-91ae-364da2661108 | www.vicarius.io | Mitigation, Third Party Advisory |
| msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21513 | [email protected] | msrc.microsoft.com | Vendor Advisory |
| www.cisa.gov/known-exploited-vulnerabilities-catalog | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | www.cisa.gov | US Government Resource |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
| CISA Known Exploited Vulnerabilities catalog | CISA | www.cisa.gov | kev |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-02-10T00:00:00.000Z | CVE-2026-21513 added to CISA KEV |
There are currently no legacy QID mappings associated with this CVE.