Microsoft’s April 2025 Patch Tuesday Updates Fix Critical Zero-Day Vulnerability

Microsoft released the April 2025 Patch Tuesday updates for Windows 10 and Windows 11 yesterday. This month, Microsoft fixed more than 120 security vulnerabilities, with one of them already being exploited by attackers.

On the quality and experience updates front, Microsoft released a new patch (KB5055523) for Windows 11 version 24H2. The latest update addresses issues affecting machine password rotation in the Identity Update Manager certificate/Pre-Bootstrapping Key Initialization path, particularly when using Kerberos and Credential Guard.

124 vulnerabilities fixed in the April 2025 Patch Tuesday updates

Among the 124 security vulnerabilities addressed with the April 2025 Patch Tuesday updates, 11 are rated Critical, two are rated Low, and the rest are rated Important in severity. Here are the most important patches you should know about this month:

• CVE-2025-29824: This is an elevation of privilege (EoP) hole in the Windows Common Log File System Driver, which is a kernel-level component responsible for managing logging for different Windows services and apps. This 7.8-rated security flaw allows hackers to gain system-level privileges on compromised machines. It affects all supported versions of Windows Server and Windows 10 and 11.
• CVE-2025-27580 and CVE-2025-27582: These security flaws are related to timing issues that could be exploited by attackers when connecting to a system with the Remote Desktop Gateway role enabled. The vulnerabilities allow hackers to execute arbitrary code on the affected system.
• CVE-2025-26663: This is a remote code execution (RCE) vulnerability in the Windows Lightweight Directory Access Protocol (LDAP). This vulnerability arises from a “use-after-free” condition, which can be exploited by an attacker to execute arbitrary code over a network.
• CVE-2025-27480, CVE-2025-27482, and CVE-2025-26663: These are critical remote code execution vulnerabilities in the Windows Lightweight Directory Access Protocol (LDAP).

Here’s the full list of patches Microsoft released this month:

Quality and experience updates

Microsoft has introduced several new features in Windows 11 version 24H2, including an AI-powered Windows Search, improved Voice Access, and enhanced Live Captions for Copilot+ PCs. Additional updates include new Top Cards in the Settings app, a taskbar emoji icon, and a gamepad layout for the touch keyboard. EU-based users also now have the option to add, remove, and rearrange lock screen widgets.

For Windows 10, Microsoft has released a couple of bug fixes for PCs running Windows 10 version 22H2. It’s important to note that Microsoft will drop support for Windows 10 on October 14, 2025, and organizations will need to pay for Extended Security Updates.

Windows Update testing and best practices

Organizations looking to deploy this month’s patches should conduct thorough testing before deploying them widely on production systems. That said, applying the patches widely shouldn’t be delayed longer than necessary as hackers start to work out how to weaponize newly reported vulnerabilities.

A best practice is to make sure you have backed up systems before applying updates. Every month, users experience issues with Windows updates that lead to systems not booting, application and hardware compatibility issues, or even data loss in extreme cases.

There are backup tools built into Windows and Windows Server that you can use to restore systems in the event a patch causes a problem. The backup features in Windows can be used to restore an entire system or files and folders on a granular basis.