Microsoft released an out-of-band security update KB5061977 on July 11, 2023, for Windows 11 to rapidly fix a critical security vulnerability. This update addresses an actively exploited zero-day vulnerability, CVE-2023-35299, in the Windows Common Log File System Driver. This flaw allowed local attackers to escalate privileges to SYSTEM level, thus gaining full control of the affected devices.

The update covers a wide range of vulnerabilities (132 in total), including zero-day exploits, privilege escalation issues, remote code execution threats, information disclosures, denial of service, and spoofing vulnerabilities. The urgency of the update reflects the immediate threat posed by this zero-day exploit, notably used by the RansomEXX ransomware group. This patch is vital for Windows 11 and Windows Server to mitigate these security risks promptly.

IT administrators are advised to prioritize deploying this update to safeguard their systems. The update is part of Microsoft’s ongoing efforts to protect the Windows ecosystem from rapid and evolving cyber threats, and it underscores the importance of timely patching to maintain system security and operational continuity.

If you want, I can provide a detailed summary of the key vulnerabilities addressed and best practices for patch deployment. Would you like that?