CVE-2026-21513
MSHTML Framework Protection Mechanism Failure in Microsoft Windows. CISA confirmed attackers exploit it and added it to its Known Exploited Vulnerabilities catalog on 10 February 2026.
- Product
- Microsoft Windows
- Added to CISA's catalog
- Federal fix-by date
- Ransomware
- No known use in ransomware campaigns
- Vendor advisories
- Sources
- CISA’s catalog, NVD entry
CISA’s description.
Microsoft MSHTML Framework contains a protection mechanism failure vulnerability that could allow an unauthorized attacker to bypass a security feature over a network.
More from Microsoft this year.
- CVE-2026-96951 Command Injection, added
- CVE-2026-65660 Code Injection, added
- CVE-2026-85880 Heap-Based Buffer Overflow, added
- CVE-2026-81963 Link Following, added
- CVE-2019-1068 Remote Code Execution, added
- CVE-2026-55040 Weak Authentication, added
- CVE-2026-33824 Double Free, added
- CVE-2026-68820 Use-After-Free, added
Every flaw CISA confirmed exploited in the last 30 days is on the exploit watch. This is not security advice. Check the vendor’s advisory before acting. From CISA’s catalog of 30 October 2026.