Windows Defender Crashes Following Security Update Fix for ShieldBreak Vulnerability

• •Windows Defender crashes during scans due to a bug in a recent security update.
• •Affected systems include Windows 10 and Windows 11, with users experiencing access violation errors.
• •Microsoft released signature update 1.457.236.0 to fix the issue and recommends users update their systems.

Microsoft has addressed a bug causing Windows Defender to crash during scans after a recent security update aimed at fixing the ShieldBreak zero-day vulnerability. Users reported access violation errors and service stoppages, leading to incomplete scans and potential vulnerabilities in their systems. The issue affected both Windows 10 and Windows 11, prompting some users to reinstall their operating systems. Microsoft confirmed the bug and released a signature update (version 1.457.236.0) to resolve the issue. Users are advised to update their systems via Windows Update to ensure they have the latest security intelligence. The problem was first reported on August 16, 2026, and has since been acknowledged by Microsoft. The crash issue was linked to the attempts to mitigate the ShieldBreak vulnerability, which allowed local users to gain SYSTEM privileges.