Enable browser legacy extension point blocking
This value is a Boolean `REG_DWORD`.
since 0.9.8.11
Purpose
Show registry keys (1)
HKLM\Software\Policies\Microsoft\Edge\BrowserLegacyExtensionPointsBlockingEnabled
This value is a Boolean REG_DWORD. A value of 1 causes Microsoft Edge to apply the Windows ProcessExtensionPointDisablePolicy mitigation to its browser process. The mitigation blocks legacy Windows extension points through which third-party applications could load code into that process.
The restriction applies to the Microsoft Edge browser process. It does not disable regular Microsoft Edge extensions or prevent every possible form of process code injection.
Notes
Security
This setting reduces the attack surface of the browser process. It prevents legacy extensibility mechanisms—such as AppInit DLLs, legacy input method editors, and certain event-based Windows hooks—from being used to load third-party code into that process.
It therefore makes persistence and injection techniques that depend on these extension points more difficult. It does not replace other security controls and blocks only the mechanisms covered by ProcessExtensionPointDisablePolicy.
Possible side effects
Legacy third-party software that must run inside the Edge browser process through one of the blocked extension points may lose its integration or stop working correctly. Microsoft identifies this type of compatibility issue as the exceptional case in which allowing legacy extension points might be necessary.
Notes
The policy is supported on Windows beginning with Microsoft Edge version 95. It is not applied per profile. A browser restart is required before a change takes effect.
Microsoft Edge also applies the process mitigation when the policy is not configured. Setting the registry value to 1 explicitly enforces that behavior as a mandatory device policy.
Microsoft documentation
Microsoft Learn: BrowserLegacyExtensionPointsBlockingEnabled
Microsoft Learn: Exploit protection reference – Disable extension points