Cookie Behavior in private browsing
Verified with Mozilla Firefox v8.2 — updated on September 2, 2026
Supported on: Firefox 95 or later, Firefox 91.4 ESR or later
Path in the GPO console
Computer Configuration\Administrative Templates\Mozilla\Firefox\Cookies User Configuration\Administrative Templates\Mozilla\Firefox\Cookies Description
If this policy is enabled, you can configure cookie behavior in private browsing. If this policy is not configured or disabled, in private browsing, cookies are rejected for known trackers and third-party cookies are partitioned.
Registry
HKLM
Software\Policies\Mozilla\Firefox\Cookies HKCU
Software\Policies\Mozilla\Firefox\Cookies 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: Cookie Behavior in private browsing
; State: Enabled
; Scope: Computer (HKLM)
; Supported on: Firefox 95 or later, Firefox 91.4 ESR or later
[HKEY_LOCAL_MACHINE\Software\Policies\Mozilla\Firefox\Cookies]
"BehaviorPrivateBrowsing"="accept"More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Cookie Behavior in private browsing
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 95 or later, Firefox 91.4 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\Cookies'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BehaviorPrivateBrowsing' -Value 'accept' -Type StringIntune 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: Cookie Behavior in private browsing
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 95 or later, Firefox 91.4 ESR 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
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Mozilla\Firefox\Cookies' -Name 'BehaviorPrivateBrowsing' -Expected 'accept' -Kind String)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Cookie Behavior in private browsing
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 95 or later, Firefox 91.4 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\Cookies'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BehaviorPrivateBrowsing' -Value 'accept' -Type StringSCCM scripts
# Exported from gporais.com
# Policy: Cookie Behavior in private browsing
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 95 or later, Firefox 91.4 ESR 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: Cookie Behavior in private browsing
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 95 or later, Firefox 91.4 ESR 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
}
$checks = @(
(Test-RegistryValue -Path 'HKLM:\Software\Policies\Mozilla\Firefox\Cookies' -Name 'BehaviorPrivateBrowsing' -Expected 'accept' -Kind String)
)
if ($checks -notcontains $false) {
Write-Output 'Compliant'
exit 0
}
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Cookie Behavior in private browsing
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 95 or later, Firefox 91.4 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\Cookies'
New-Item -Path $path -Force | Out-Null
Set-ItemProperty -Path $path -Name 'BehaviorPrivateBrowsing' -Value 'accept' -Type StringBuilding a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.