Actively Exploited Outlook and Exchange Flaws Patched by Microsoft
Active Exploitation · 2 sources · Updated 4mo ago · First seen Jan 25, 2026
Microsoft patched multiple actively exploited vulnerabilities across Windows, Outlook, Office, and Exchange Server, including the Outlook flaw CVE-2024-21413 and the Exchange Server issue CVE-2024-21410. The February Patch Tuesday release addressed 73 vulnerabilities in total, with five rated critical, and included fixes for additional zero-days such as CVE-2024-21412 involving Internet Shortcut/LNK files and CVE-2024-21351, a security feature bypass used in attacks.
The Outlook vulnerability CVE-2024-21413 stems from improper parsing of file:// links, allowing attackers to bypass Protected View, leak NTLM credentials, and potentially achieve remote code execution. In Exchange Server, CVE-2024-21410 allows an unauthenticated attacker to capture and relay Net-NTLMv2 authentication material; defenders were urged to apply Microsoft’s security updates immediately and enable Extended Protection for Authentication on Exchange systems.
