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// graph-permissions · MailboxItem

MailboxItem.ReadWrite.AllMicrosoft Graph permission · High risk

Allows the app to read, write, and delete all users' mailbox items, without a signed-in user.

Application permission

High risk

Read and write all users' mailbox items. Allows the app to read, write, and delete all users' mailbox items, without a signed-in user.

ID1583d471-fede-4e7c-b062-57e9d60cfb49
ConsentAlways needs admin consent
RiskCan change data across the whole tenant.

Grant it to an app

In the portal: App registrations › your app › API permissions › Add a permission › Microsoft Graph › Application permissions, then grant admin consent. Or with Graph PowerShell:

powershell5 lines
Connect-MgGraph -Scopes "Application.Read.All", "AppRoleAssignment.ReadWrite.All"
$graph = Get-MgServicePrincipal -Filter "appId eq '00000003-0000-0000-c000-000000000000'"
$app   = Get-MgServicePrincipal -Filter "appId eq '<your app's client id>'"
New-MgServicePrincipalAppRoleAssignment -ServicePrincipalId $app.Id `
    -PrincipalId $app.Id -ResourceId $graph.Id -AppRoleId "1583d471-fede-4e7c-b062-57e9d60cfb49"

Which apps already have it?

powershell6 lines
# Apps that hold MailboxItem.ReadWrite.All as an application permission
Connect-MgGraph -Scopes "Application.Read.All"
$graph = Get-MgServicePrincipal -Filter "appId eq '00000003-0000-0000-c000-000000000000'"
Get-MgServicePrincipalAppRoleAssignedTo -ServicePrincipalId $graph.Id -All |
    Where-Object AppRoleId -eq "1583d471-fede-4e7c-b062-57e9d60cfb49" |
    Select-Object PrincipalDisplayName, PrincipalId, CreatedDateTime

Other MailboxItem permissions

Check every app in your tenant → Permission explainer

Sources