Block the Serial API on these sites
Verified with Google Chrome — updated on July 10, 2026
Supported on: Microsoft Windows 7 or later
Path in the GPO console
Computer Configuration\Administrative Templates\Google\Google Chrome\Content settings User Configuration\Administrative Templates\Google\Google Chrome\Content settings Description
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
Registry
Software\Policies\Google\Chrome Software\Policies\Google\Chrome Export Builder
BETAConfigure the state, scope and options, then generate .reg, PowerShell, Intune and SCCM outputs — or add the setting to a multi-setting collection.
These exports write the registry — this is not a managed GPO. ⓘ
Applying both scopes creates an ambiguous configuration (computer takes precedence over user). Only do this intentionally.
.reg file
Windows Registry Editor Version 5.00
; Exported from gporais.com
; Policy: Block the Serial API on these sites
; State: Enabled
; Scope: Computer (HKLM)
; Supported on: Microsoft Windows 7 or later
[HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\SerialBlockedForUrls]
; List values: enter one value per line in the builder UI.More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Block the Serial API on these sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Microsoft Windows 7 or later
$path = 'HKLM:\Software\Policies\Google\Chrome\SerialBlockedForUrls'
New-Item -Path $path -Force | Out-Null
# List values: enter one value per line in the builder UI.Intune XML
No direct Policy CSP / OMA-URI mapping for this policy. Use the Intune Remediation tab, or ingest the ADMX in Intune.Intune Remediation
# === Detection script ===
# Exported from gporais.com
# Policy: Block the Serial API on these sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Microsoft Windows 7 or later
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
# HKLM:\Software\Policies\Google\Chrome\SerialBlockedForUrls: List values: enter one value per line in the builder UI.
# No testable registry values are available for this state.
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Block the Serial API on these sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Microsoft Windows 7 or later
$path = 'HKLM:\Software\Policies\Google\Chrome\SerialBlockedForUrls'
New-Item -Path $path -Force | Out-Null
# List values: enter one value per line in the builder UI.SCCM scripts
# Exported from gporais.com
# Policy: Block the Serial API on these sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Microsoft Windows 7 or later
# SCCM Configuration Item guidance:
# Create a Configuration Item of type "Setting: Script".
# Discovery script: use the Detection script below.
# Remediation script: use the Remediation script below.
# Compliance rule: the Discovery script output equals 'Compliant'.
# === Detection script ===
# Exported from gporais.com
# Policy: Block the Serial API on these sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Microsoft Windows 7 or later
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
# HKLM:\Software\Policies\Google\Chrome\SerialBlockedForUrls: List values: enter one value per line in the builder UI.
# No testable registry values are available for this state.
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Block the Serial API on these sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Microsoft Windows 7 or later
$path = 'HKLM:\Software\Policies\Google\Chrome\SerialBlockedForUrls'
New-Item -Path $path -Force | Out-Null
# List values: enter one value per line in the builder UI.Building a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.