Block the Serial API on these sites

Computer and userIntune-readySerialBlockedForUrls

Supported on Microsoft Windows 7 or later

155.0.8059.85

What it does

Setting the policy lets you list the URL patterns that specify which sites can't ask users to grant them access to a serial port. Leaving the policy unset means DefaultSerialGuardSetting applies for all sites, if it's set. If not, the user's personal setting applies. For URL patterns which do not match the policy SerialAskForUrls (if there is a match), DefaultSerialGuardSetting (if set), or the users' personal settings take precedence, in that order. If URL patterns conflict with SerialAskForUrls this policy will take precedence. For detailed information on valid url patterns, please see https://chromeenterprise.google/policies/url-patterns. * is not an accepted value for this policy. Example value: https://www.example.com [*.]example.edu

What it writes

Hive: HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
Registry key: Software\Policies\Google\Chrome

Options

Option	Type	Registry value	Allowed values
Block the Serial API on these sites	List of values	`Software\Policies\Google\Chrome\SerialBlockedForUrls`	Any

Configure and deploy

Choose a state and the option values; 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\Google\Chrome\SerialBlockedForUrls]

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: Block the Serial API on these sites
# Name: SerialBlockedForUrls
# Scope: Machine
# State: Enabled
# Source: chrome.admx

Clear-RegistryKeyValues -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\SerialBlockedForUrls'

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.
The generated payload is incomplete because one or more ADMX element values were not supplied: SerialBlockedForUrlsDesc

ADMX profile candidate (OMA-URI)

./Device/Vendor/MSFT/Policy/Config/ADMX_chrome/SerialBlockedForUrls

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: Block the Serial API on these sites
# Name: SerialBlockedForUrls
# Scope: Machine
# State: Enabled
# Source: chrome.admx

$keyPath = 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\SerialBlockedForUrls'
if (Test-Path -LiteralPath $keyPath) {
    $propertyNames = (Get-Item -LiteralPath $keyPath).Property
    if ($propertyNames.Count -gt 0) {
        $reasons.Add('Key should be empty: HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\SerialBlockedForUrls') | 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: Block the Serial API on these sites
# Name: SerialBlockedForUrls
# Scope: Machine
# State: Enabled
# Source: chrome.admx

Clear-RegistryKeyValues -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\SerialBlockedForUrls'

History 1 retained release

155.0.8059.8519 Oct 2026
- Already present in the first release ChangeIntel keeps.

Template

Internal name: SerialBlockedForUrls
Namespace: Google.Policies.Chrome
Template file: chrome.admx
Release: Google Chrome 155.0.8059.85 · file set 1f03ffd12695d620…

Definition, editor controls and support

Definition

<policy class="Both" displayName="$(string.SerialBlockedForUrls)" explainText="$(string.SerialBlockedForUrls_Explain)" key="Software\Policies\Google\Chrome" name="SerialBlockedForUrls" presentation="$(presentation.SerialBlockedForUrls)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies.Chrome:ContentSettings" />
      <supportedOn ref="Google.Policies.Chrome:SUPPORTED_WIN7" />
      <elements>
        <list id="SerialBlockedForUrlsDesc" key="Software\Policies\Google\Chrome\SerialBlockedForUrls" valuePrefix="" />
      </elements>
    </policy>

Editor controls

<presentation id="SerialBlockedForUrls" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions"><listBox refId="SerialBlockedForUrlsDesc">Block the Serial API on these sites</listBox></presentation>

Supported platforms and category

Google.Policies.Chrome:category:ContentSettings
<category displayName="$(string.ContentSettings_group)" name="ContentSettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies.Chrome:googlechrome" />
    </category>
Google.Policies.Chrome:category:googlechrome
<category displayName="$(string.googlechrome)" name="googlechrome" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies:Cat_Google" />
    </category>
Google.Policies.Chrome:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Google.Policies:category:Cat_Google
<category displayName="$(string.google)" name="Cat_Google" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Google.Policies.Chrome:category:ContentSettings
<category displayName="$(string.ContentSettings_group)" name="ContentSettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies.Chrome:googlechrome" />
    </category>
<strings><string id="Google.Policies.Chrome:ContentSettings_group">Content settings</string></strings>
Google.Policies.Chrome:category:googlechrome
<category displayName="$(string.googlechrome)" name="googlechrome" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies:Cat_Google" />
    </category>
<strings><string id="Google.Policies.Chrome:googlechrome">Google Chrome</string></strings>
Google.Policies.Chrome:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Google.Policies.Chrome:SUPPORTED_WIN7">Microsoft Windows 7 or later</string></strings>
Google.Policies:category:Cat_Google
<category displayName="$(string.google)" name="Cat_Google" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Google.Policies:google">Google</string></strings>