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

Computer and userIntune-readyAccessControlAllowMethodsInCORSPreflightSpecConformant

Supported on Microsoft Edge version 123, Windows 7 or later

155.0.4283.62

What it does

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 aren't 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" aren't affected, while "patch" is affected. This policy is intended to be temporary and will be removed in the future.

What it writes

Hive: HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
Registry key: Software\Policies\Microsoft\Edge\WebView2
Value name: AccessControlAllowMethodsInCORSPreflightSpecConformant
When enabled: DWORD 1
When disabled: DWORD 0

Configure and deploy

Choose a state; the output below is generated from the template for exactly that.

Enabled · Computer · template defaults

Registry file (.reg)

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge\WebView2]
"AccessControlAllowMethodsInCORSPreflightSpecConformant"=dword:00000001

PowerShell

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Make Access-Control-Allow-Methods matching in CORS preflight spec conformant
# Name: AccessControlAllowMethodsInCORSPreflightSpecConformant
# Scope: Machine
# State: Enabled
# Source: msedgewebview2.admx

Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge\WebView2' -Name 'AccessControlAllowMethodsInCORSPreflightSpecConformant' -PropertyType 'DWord' -Value 1

The OMA-URI is an inferred ADMX-backed Policy CSP candidate derived from the source ADMX file name and policy name.
Some Microsoft policies use built-in Policy CSP pages whose area names don't match the ADMX file name, so verify the candidate against Microsoft Learn before deployment.

ADMX profile candidate (OMA-URI)

./Device/Vendor/MSFT/Policy/Config/ADMX_msedgewebview2/AccessControlAllowMethodsInCORSPreflightSpecConformant

ADMX SyncML candidate

<SyncML xmlns="SYNCML:SYNCML1.2">
  <SyncBody>
    <Replace>
      <CmdID>1</CmdID>
      <Item>
        <Meta>
          <Format>chr</Format>
          <Type>text/plain</Type>
        </Meta>
        <Target>
          <LocURI>./Device/Vendor/MSFT/Policy/Config/ADMX_msedgewebview2/AccessControlAllowMethodsInCORSPreflightSpecConformant</LocURI>
        </Target>
        <Data>&lt;enabled/&gt;</Data>
      </Item>
    </Replace>
    <Final/>
  </SyncBody>
</SyncML>

Intune remediation scripts

Detection

$ErrorActionPreference = 'Stop'
$reasons = [System.Collections.Generic.List[string]]::new()

function Test-RegistryValueExists {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    return $null -ne (Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue)
}

function Test-RegistryValueEquals {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $Kind,
        [Parameter(Mandatory = $true)][object] $Expected
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    $valueObject = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue
    if ($null -eq $valueObject) {
        return $false
    }

    $actual = $valueObject.$Name
    switch ($Kind) {
        'String' { return [string]$actual -ceq [string]$Expected }
        'ExpandString' { return [string]$actual -ceq [string]$Expected }
        'DWord' { return [uint32]$actual -eq [uint32]$Expected }
        'QWord' { return [uint64]$actual -eq [uint64]$Expected }
        'MultiString' {
            $actualArray = @($actual)
            $expectedArray = @($Expected)
            if ($actualArray.Count -ne $expectedArray.Count) { return $false }
            for ($index = 0; $index -lt $actualArray.Count; $index++) {
                if ([string]$actualArray[$index] -cne [string]$expectedArray[$index]) { return $false }
            }
            return $true
        }
        'Binary' {
            $actualArray = [byte[]]$actual
            $expectedArray = [byte[]]$Expected
            if ($actualArray.Length -ne $expectedArray.Length) { return $false }
            for ($index = 0; $index -lt $actualArray.Length; $index++) {
                if ($actualArray[$index] -ne $expectedArray[$index]) { return $false }
            }
            return $true
        }
        default { return [string]$actual -ceq [string]$Expected }
    }
}

# Policy: Make Access-Control-Allow-Methods matching in CORS preflight spec conformant
# Name: AccessControlAllowMethodsInCORSPreflightSpecConformant
# Scope: Machine
# State: Enabled
# Source: msedgewebview2.admx

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge\WebView2' -Name 'AccessControlAllowMethodsInCORSPreflightSpecConformant' -Kind 'DWord' -Expected 1
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge\WebView2\AccessControlAllowMethodsInCORSPreflightSpecConformant') | Out-Null
}

if ($reasons.Count -eq 0) {
    Write-Output 'Compliant'
    exit 0
}

$reasons | ForEach-Object { Write-Output $_ }
exit 1

Remediation

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Make Access-Control-Allow-Methods matching in CORS preflight spec conformant
# Name: AccessControlAllowMethodsInCORSPreflightSpecConformant
# Scope: Machine
# State: Enabled
# Source: msedgewebview2.admx

Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Edge\WebView2' -Name 'AccessControlAllowMethodsInCORSPreflightSpecConformant' -PropertyType 'DWord' -Value 1

History 37 retained releases

150.0.4078.8016 Jul 2026
- Already present in the first release ChangeIntel keeps.

36 later releases left it unchanged.

Template

Internal name: AccessControlAllowMethodsInCORSPreflightSpecConformant
Namespace: Microsoft.Policies.WebView2
Template file: msedgewebview2.admx
Release: Microsoft Edge 155.0.4283.62 · file set 0a733b0040dbbf02…

Definition, editor controls and support

Definition

<policy class="Both" displayName="$(string.AccessControlAllowMethodsInCORSPreflightSpecConformant)" explainText="$(string.AccessControlAllowMethodsInCORSPreflightSpecConformant_Explain)" key="Software\Policies\Microsoft\Edge\WebView2" name="AccessControlAllowMethodsInCORSPreflightSpecConformant" presentation="$(presentation.AccessControlAllowMethodsInCORSPreflightSpecConformant)" valueName="AccessControlAllowMethodsInCORSPreflightSpecConformant" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.WebView2:Network" />
      <supportedOn ref="Microsoft.Policies.WebView2:SUPPORTED_WIN7_V123" />
      <enabledValue>
        <decimal value="1" />
      </enabledValue>
      <disabledValue>
        <decimal value="0" />
      </disabledValue>
    </policy>

Editor controls

<presentation id="AccessControlAllowMethodsInCORSPreflightSpecConformant" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />

Supported platforms and category

Microsoft.Policies.WebView2:category:Network
<category displayName="$(string.Network_group)" name="Network" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.WebView2:microsoft_edge_webview2" />
    </category>
Microsoft.Policies.WebView2:category:microsoft_edge_webview2
<category displayName="$(string.microsoft_edge_webview2)" name="microsoft_edge_webview2" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Microsoft.Policies.WebView2:definition:SUPPORTED_WIN7_V123
<definition displayName="$(string.SUPPORTED_WIN7_V123)" name="SUPPORTED_WIN7_V123" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Microsoft.Policies.WebView2:category:Network
<category displayName="$(string.Network_group)" name="Network" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Microsoft.Policies.WebView2:microsoft_edge_webview2" />
    </category>
<strings><string id="Microsoft.Policies.WebView2:Network_group">Network settings</string></strings>
Microsoft.Policies.WebView2:category:microsoft_edge_webview2
<category displayName="$(string.microsoft_edge_webview2)" name="microsoft_edge_webview2" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Microsoft.Policies.WebView2:microsoft_edge_webview2">Microsoft Edge WebView2</string></strings>
Microsoft.Policies.WebView2:definition:SUPPORTED_WIN7_V123
<definition displayName="$(string.SUPPORTED_WIN7_V123)" name="SUPPORTED_WIN7_V123" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Microsoft.Policies.WebView2:SUPPORTED_WIN7_V123">Microsoft Edge version 123, Windows 7 or later</string></strings>