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CVE-2026-21513MSHTML Framework Security Feature Bypass Vulnerability
Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.
8.8 HIGHEPSS 15.85%⚡ Known Exploited (CISA KEV)NVD: Analyzed
Overview
Severity
| Score | Severity | Version | Vector String |
|---|---|---|---|
| 8.8 | HIGH | 3.1microsoft (CNA) | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| 8.8 | HIGH | 3.1microsoft (CNA) | 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 |
CISA required action
⚡ Known exploited · remediation due Mar 3, 2026
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Details
- CVE ID
- CVE-2026-21513
- Status
- Analyzed
- Assigner (CNA)
- microsoft
- Published
- Feb 10, 2026
- Last modified
- 2026-08-19 16:25 UTC
- Weaknesses
- CWE-693 · Protection Mechanism Failure
Affected Products
As published by the CNA in the CVE record.
MicrosoftWindows 10 Version 16071 version range
- 10.0.14393.0 before 10.0.14393.8868
MicrosoftWindows 10 Version 18091 version range
- 10.0.17763.0 before 10.0.17763.8389
MicrosoftWindows 10 Version 21H21 version range
- 10.0.19044.0 before 10.0.19044.6937
MicrosoftWindows 10 Version 22H21 version range
- 10.0.19045.0 before 10.0.19045.6937
MicrosoftWindows 11 version 22H31 version range
- 10.0.22631.0 before 10.0.22631.6649
MicrosoftWindows 11 Version 23H21 version range
- 10.0.22631.0 before 10.0.22631.6649
MicrosoftWindows 11 Version 24H21 version range
- 10.0.26100.0 before 10.0.26100.7840
MicrosoftWindows 11 Version 25H21 version range
- 10.0.26200.0 before 10.0.26200.7840
MicrosoftWindows 11 version 26H11 version range
- 10.0.28000.0 before 10.0.28000.1575
MicrosoftWindows 11 Version 26H11 version range
- 10.0.28000.0 before 10.0.28000.1575
MicrosoftWindows Server 20121 version range
- 6.2.9200.0 before 6.2.9200.25923
MicrosoftWindows Server 2012 (Server Core installation)1 version range
- 6.2.9200.0 before 6.2.9200.25923
MicrosoftWindows Server 2012 R21 version range
- 6.3.9600.0 before 6.3.9600.23022
MicrosoftWindows Server 2012 R2 (Server Core installation)1 version range
- 6.3.9600.0 before 6.3.9600.23022
MicrosoftWindows Server 20161 version range
- 10.0.14393.0 before 10.0.14393.8868
MicrosoftWindows Server 2016 (Server Core installation)1 version range
- 10.0.14393.0 before 10.0.14393.8868
MicrosoftWindows Server 20191 version range
- 10.0.17763.0 before 10.0.17763.8389
MicrosoftWindows Server 2019 (Server Core installation)1 version range
- 10.0.17763.0 before 10.0.17763.8389
MicrosoftWindows Server 20221 version range
- 10.0.20348.0 before 10.0.20348.4773
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)1 version range
- 10.0.25398.0 before 10.0.25398.2149
MicrosoftWindows Server 20251 version range
- 10.0.26100.0 before 10.0.26100.32370
MicrosoftWindows Server 2025 (Server Core installation)1 version range
- 10.0.26100.0 before 10.0.26100.32370
References
- msrc.microsoft.com https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21513
- vicarius.io https://www.vicarius.io/vsociety/posts/cve-2026-21513-detection-script-security-feature-bypass-vulnerability-in-mshtml-framework
- vicarius.io https://www.vicarius.io/vsociety/posts/cve-2026-21513-mitigation-script-security-feature-bypass-vulnerability-in-mshtml-framework
- cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21513