Vulnerabilities · 197 days ago

APT28 Tied to CVE-2026-21513 MSHTML 0-Day Exploited Before Feb 2026 Patch Tuesday

APT28 exploited CVE-2026-21513, an MSHTML zero-day (CVSS 8.8), using malicious LNK files to bypass security controls and execute code.

CVE-2026-21513

NVD KEV

Known exploited · CISA KEV

CVSS 8.8 HIGH: protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a… EPSS 16% (97th percentile). Microsoft patch: 5077179.

Patch available KB5077179 Download →

CISA federal remediation date Mar 3

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Vendor digest: Microsoft

Part of the PlainSec briefing for 2026-03-07

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