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// graph-permissions · MailboxSettings

MailboxSettings.ReadMicrosoft Graph permission · High risk

Allows the app to read user's mailbox settings without a signed-in user. Does not include permission to send mail.

Application permission

High risk

Read all user mailbox settings. Allows the app to read user's mailbox settings without a signed-in user. Does not include permission to send mail.

ID40f97065-369a-49f4-947c-6a255697ae91
ConsentAlways needs admin consent
RiskAs an application permission this reaches every user's data in the tenant, without anyone signed in.

Delegated permission

Medium risk

Read user mailbox settings. Allows the app to the read user's mailbox settings. Does not include permission to send mail.

ID87f447af-9fa4-4c32-9dfa-4a57a73d18ce
ConsentUsers can consent, if your consent settings allow it
RiskReads or changes the signed-in user's content, limited to what that user can access.

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 "40f97065-369a-49f4-947c-6a255697ae91"

Ask for it when signing in

Delegated permissions act as the signed-in user, so the app can never do more than that user can.

powershell1 line
Connect-MgGraph -Scopes "MailboxSettings.Read"

Which apps already have it?

powershell6 lines
# Apps that hold MailboxSettings.Read 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 "40f97065-369a-49f4-947c-6a255697ae91" |
    Select-Object PrincipalDisplayName, PrincipalId, CreatedDateTime
powershell6 lines
# Apps with delegated consent for MailboxSettings.Read
Connect-MgGraph -Scopes "Application.Read.All", "Directory.Read.All"
$graph = Get-MgServicePrincipal -Filter "appId eq '00000003-0000-0000-c000-000000000000'"
Get-MgOauth2PermissionGrant -All |
    Where-Object { $_.ResourceId -eq $graph.Id -and ($_.Scope -split " ") -contains "MailboxSettings.Read" } |
    Select-Object ClientId, ConsentType, PrincipalId

Other MailboxSettings permissions

Check every app in your tenant → Permission explainer

Sources