Microsoft MSHTML known exploited vulnerabilities
We track 3 CVEs in Microsoft MSHTML. All of them are on CISA's Known Exploited Vulnerabilities catalog, meaning CISA has evidence of exploitation in the wild (listed 2021–2026). CISA flags 1 of them as used in ransomware campaigns. The most recent is CVE-2026-21513, added to KEV on .
Also listed as: MSHTML Framework (Windows) · Windows MSHTML. CISA, NVD and vendor advisories name the same product differently; each CVE page keeps the wording from its source.
- CVEs tracked
- 3
- On CISA KEV
- 3
- Ransomware use
- 1
- Rated critical
- 0
Every Microsoft MSHTML CVE we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV | Patch by |
|---|---|---|---|---|---|
| CVE-2026-21513 Microsoft MSHTML security feature bypasswrite-up | [ HIGH ] | 8.8 | 15.9% | ||
| CVE-2021-40444 MSHTML Remote Code Execution via Malicious Office Documentransomware usewrite-up | [ HIGH ] | 8.8 | 97.8% | ||
| CVE-2019-0541 Microsoft MSHTML Remote Code Execution Vulnerability | [ HIGH ] | 8.8 | 53.2% |
Sorted by date added to KEV. Severity and CVSS as stated by NVD or the vendor; EPSS from FIRST.org. "Patch by" is CISA's BOD 22-01 deadline for US federal agencies, a useful priority signal for everyone else. Machine-readable: /api/v1/vendors/microsoft.json.
Our Microsoft MSHTML coverage
Other Microsoft products
Every row links to its CVE record with the CISA required action, catalog coverage and primary sources. We describe impact and remediation only; no exploit code. See the full KEV tracker or compare KEV catalogs.