MSRXVulnerabilities / CVE-2026-21513
CVE-2026-21513
Published 2026-02-10 · Analyzed
CVE-2026-21513
Microsoft MSHTML Framework Protection Mechanism Failure Vulnerability
Exploited in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2026-02-10, with a fix-by date of 2026-03-03. Patch it first.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
8.8 HIGH
CVSS 3.1 · CNA · microsoft.com
CVSS 3.1 · CNA · microsoft.com
16%
chance of exploitation in the next 30 days (EPSS; higher than 96% of CVEs)
chance of exploitation in the next 30 days (EPSS; higher than 96% of CVEs)
Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.
Scores
Affected products
- microsoft windows 10 1607: < 10.0.14393.8868
- microsoft windows 10 1809: < 10.0.17763.8389
- microsoft windows 10 21h2: < 10.0.19044.6937
- microsoft windows 10 22h2: < 10.0.19045.6937
- microsoft windows 11 23h2: < 10.0.22631.6649
- microsoft windows 11 24h2: < 10.0.26100.7781
- microsoft windows 11 25h2: < 10.0.26200.7781
- microsoft windows server 2012: all versions; r2
- microsoft windows server 2016: < 10.0.14393.8868
- microsoft windows server 2019: < 10.0.17763.8389
- microsoft windows server 2022: < 10.0.20348.4711
- microsoft windows server 2022 23h2: < 10.0.25398.2149
- microsoft windows server 2025: < 10.0.26100.32313
Weakness: CWE-693
4 references (advisories, patches, write-ups)
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21513 · Vendor Advisory
- https://www.vicarius.io/vsociety/posts/cve-2026-21513-detection-script-security-feature-bypass-vulnerability-in-mshtml-framework · Third Party Advisory
- https://www.vicarius.io/vsociety/posts/cve-2026-21513-mitigation-script-security-feature-bypass-vulnerability-in-mshtml-framework · Mitigation, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21513 · US Government Resource
Sources: NVD, CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.