Windows 10 KB5049981, Windows 11 KB5050009 & KB5050021 Security Updates

Windows 10 KB5049981, Windows 11 KB5050009 & KB5050021 Security Updates
Microsoft has released security updates for Windows 10 and Windows 11, which include new features and address various vulnerabilities. Notably, the updates introduce a blocklist for vulnerable kernel drivers and highlight known issues affecting SSH connections and Citrix configurations. Affected: Windows 10, Windows 11, Citrix

Keypoints :

  • Microsoft has provided security updates for Windows 10 (KB5049981) and Windows 11 (KB5050009, KB5050021).
  • The updates include a blocklist file for vulnerable kernel drivers to prevent privilege escalation.
  • Known issues include SSH service failures due to the update and installation problems for devices with specific Citrix configurations.
  • Windows 11 version 24H2 has a new build number of 26100.2605.
  • File Explorer enhancements allow sharing content with Android devices via Phone Link.
  • Improvements in voice-to-text and text-to-speech functionalities have been made.
  • Multiple vulnerabilities have been identified, including remote code execution vulnerabilities.

MITRE Techniques :

  • TA0001 – Initial Access: Exploitation of vulnerabilities in Microsoft Digest Authentication (CVE-2025-21294).
  • TA0001 – Initial Access: Exploitation of SPNEGO extension negotiation (CVE-2025-21295).
  • TA0001 – Initial Access: Exploitation of BranchCache vulnerabilities (CVE-2025-21296).
  • TA0001 – Initial Access: Exploitation of Windows OLE vulnerabilities (CVE-2025-21298).
  • TA0001 – Initial Access: Exploitation of RMCAST vulnerabilities (CVE-2025-21307).

Indicator of Compromise :

  • [file hash] CVE-2025-21294
  • [file hash] CVE-2025-21295
  • [file hash] CVE-2025-21296
  • [file hash] CVE-2025-21298
  • [file hash] CVE-2025-21307
  • Check the article for all found IoCs.



Full Research: https://wezard4u.tistory.com/429384