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AccessControlAllowMethodsInCORSPreflightSpecConformant

Make Access-Control-Allow-Methods matching in CORS preflight spec conformant

Supported versions

  • On Windows and macOS since 123 or later

Description

This policy controls whether request methods are uppercased when matching with Access-Control-Allow-Methods response headers in CORS preflight.

If you disable this policy, request methods are uppercased. This is the behavior on or before Microsoft Edge 108.

If you enable or don't configure this policy, request methods are not uppercased, unless matching case-insensitively with DELETE, GET, HEAD, OPTIONS, POST, or PUT.

This would reject fetch(url, {method: 'Foo'}) + "Access-Control-Allow-Methods: FOO" response header, and would accept fetch(url, {method: 'Foo'}) + "Access-Control-Allow-Methods: Foo" response header.

Note: request methods "post" and "put" are not affected, while "patch" is affected.

This policy is intended to be temporary and will be removed in the future.

Supported features

  • Can be mandatory: Yes
  • Can be recommended: No
  • Dynamic Policy Refresh: No - Requires browser restart
  • Per Profile: Yes
  • Applies to a profile that is signed in with a Microsoft account: No

Data type

  • Boolean

Windows information and settings

Group Policy (ADMX) info

  • GP unique name: AccessControlAllowMethodsInCORSPreflightSpecConformant
  • GP name: Make Access-Control-Allow-Methods matching in CORS preflight spec conformant
  • GP path (Mandatory): Administrative Templates/Microsoft Edge/Network settings
  • GP path (Recommended): N/A
  • GP ADMX file name: MSEdge.admx

Example value

Enabled

Registry settings

  • Path (Mandatory): SOFTWARE\Policies\Microsoft\Edge
  • Path (Recommended): N/A
  • Value name: AccessControlAllowMethodsInCORSPreflightSpecConformant
  • Value type: REG_DWORD

Example registry value

0x00000001

Mac information and settings

  • Preference Key name: AccessControlAllowMethodsInCORSPreflightSpecConformant
  • Example value:
<true/>

See also