Brave Software › Brave
Enable opaque origins for data URLs in Web Workers
Supported on Microsoft Windows 7 or later
What it does
Controls whether Web Workers created from data URLs are assigned a unique opaque origin. Web Workers can be created using a data URL containing the worker's script. Previously, these workers inherited the origin of the page that created them, allowing them to access the same local storage, cookies, and other origin-bound data. To improve security and align with the HTML specification, Chrome is changing its default behavior in milestone 149 so that workers created from data URLs will now have a unique, opaque origin. This isolates them from the creator page's data. If this policy is set to Enabled or left unset, the new default (more secure) behavior is used, and Web Workers created from data URLs will have a unique opaque origin. If this policy is set to Disabled, Chrome reverts to the legacy behavior, and Web Workers created from data URLs will inherit the origin of their creator. This allows administrators to temporarily resolve compatibility issues if internal applications break due to the security change. This policy is intended to be temporary and will be removed in milestone 157.
What it writes
- Hive
- HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
- Registry key
Software\Policies\BraveSoftware\Brave- Value name
DataUrlInWebWorkerOpaqueOriginEnabled- 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\BraveSoftware\Brave]
"DataUrlInWebWorkerOpaqueOriginEnabled"=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: Enable opaque origins for data URLs in Web Workers
# Name: DataUrlInWebWorkerOpaqueOriginEnabled
# Scope: Machine
# State: Enabled
# Source: brave.admx
Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave' -Name 'DataUrlInWebWorkerOpaqueOriginEnabled' -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_brave/DataUrlInWebWorkerOpaqueOriginEnabledADMX 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_brave/DataUrlInWebWorkerOpaqueOriginEnabled</LocURI>
</Target>
<Data><enabled/></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: Enable opaque origins for data URLs in Web Workers
# Name: DataUrlInWebWorkerOpaqueOriginEnabled
# Scope: Machine
# State: Enabled
# Source: brave.admx
$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave' -Name 'DataUrlInWebWorkerOpaqueOriginEnabled' -Kind 'DWord' -Expected 1
if (-not $isMatch) {
$reasons.Add('Value mismatch: HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave\DataUrlInWebWorkerOpaqueOriginEnabled') | Out-Null
}
if ($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 $propertyName -Force -ErrorAction SilentlyContinue
}
}
# Policy: Enable opaque origins for data URLs in Web Workers
# Name: DataUrlInWebWorkerOpaqueOriginEnabled
# Scope: Machine
# State: Enabled
# Source: brave.admx
Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave' -Name 'DataUrlInWebWorkerOpaqueOriginEnabled' -PropertyType 'DWord' -Value 1
History 44 retained releases
- 1.91.1683 Jun 2026
- Added in this release.
30 later releases left it unchanged.
Template
- Internal name
DataUrlInWebWorkerOpaqueOriginEnabled- Namespace
BraveSoftware.Policies.Brave- Template file
brave.admx- Release
- Brave Browser 1.97.59 · file set
d6401efd8c1937d9…
Definition, editor controls and support
Definition
<policy class="Both" displayName="$(string.DataUrlInWebWorkerOpaqueOriginEnabled)" explainText="$(string.DataUrlInWebWorkerOpaqueOriginEnabled_Explain)" key="Software\Policies\BraveSoftware\Brave" name="DataUrlInWebWorkerOpaqueOriginEnabled" presentation="$(presentation.DataUrlInWebWorkerOpaqueOriginEnabled)" valueName="DataUrlInWebWorkerOpaqueOriginEnabled" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="BraveSoftware.Policies.Brave:brave" />
<supportedOn ref="BraveSoftware.Policies.Brave:SUPPORTED_WIN7" />
<enabledValue>
<decimal value="1" />
</enabledValue>
<disabledValue>
<decimal value="0" />
</disabledValue>
</policy>Editor controls
<presentation id="DataUrlInWebWorkerOpaqueOriginEnabled" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />Supported platforms and category
BraveSoftware.Policies.Brave:category:Cat_Brave
<category displayName="$(string.Cat_Brave)" name="Cat_Brave" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
BraveSoftware.Policies.Brave:category:brave
<category displayName="$(string.brave)" name="brave" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="BraveSoftware.Policies.Brave:Cat_Brave" />
</category>
BraveSoftware.Policies.Brave:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
BraveSoftware.Policies.Brave:category:Cat_Brave
<category displayName="$(string.Cat_Brave)" name="Cat_Brave" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="BraveSoftware.Policies.Brave:Cat_Brave">Brave Software</string></strings>
BraveSoftware.Policies.Brave:category:brave
<category displayName="$(string.brave)" name="brave" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="BraveSoftware.Policies.Brave:Cat_Brave" />
</category>
<strings><string id="BraveSoftware.Policies.Brave:brave">Brave</string></strings>
BraveSoftware.Policies.Brave:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="BraveSoftware.Policies.Brave:SUPPORTED_WIN7">Microsoft Windows 7 or later</string></strings>