Windows 11 Gets Batch File Security Upgrade — Lock Files During Execution to Prevent Tampering

Q: How It Works

The new LockBatchFilesInUse registry value, added under HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor, enables a more secure processing mode for CMD scripts. When enabled, batch files are locked during execution so they cannot be modified by other processes — closing a vector that attackers have exploited to inject malicious commands into running scripts. Policy authors can also enable this mode using the LockBatchFilesWhenInUse application manifest control, giving organizations more granular deployment options.

By SaveDelete February 28, 2026 Updated: February 28, 2026

Microsoft is rolling out a security improvement to Windows 11 that addresses a surprisingly old vulnerability: batch files that can be modified while they're running. The new feature, currently in Insider Preview builds, lets administrators lock batch files during execution — preventing tampering that could redirect script behavior mid-process.

How It Works

The new LockBatchFilesInUse registry value, added under HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor, enables a more secure processing mode for CMD scripts. When enabled, batch files are locked during execution so they cannot be modified by other processes — closing a vector that attackers have exploited to inject malicious commands into running scripts.

Policy authors can also enable this mode using the LockBatchFilesWhenInUse application manifest control, giving organizations more granular deployment options.

Performance Benefits

Beyond security, the change delivers a notable performance improvement. When code integrity checking is enabled, Windows currently validates the signature of batch files on every statement executed. With the new locking mechanism, validation only needs to happen once at the start of execution — significantly reducing overhead for complex scripts.

Who Gets It First?

The feature is rolling out to Windows Insiders in both the Beta Channel (Build 26220.7934) and Dev Channel (Build 26300.7939). Enterprise administrators who rely heavily on batch file automation will benefit most, though the security improvement applies to all Windows 11 users once it reaches general availability.

The Bottom Line

Batch files have been a Windows staple since the MS-DOS era, and the fact that they could be modified during execution in 2026 is genuinely surprising. This fix is long overdue — it's a small but meaningful security improvement that closes a gap attackers have known about for decades. The performance boost is a welcome bonus for enterprise environments still running heavy batch automation.

Source: BleepingComputer