Granting app permissions to a specific SharePoint subsite causes a "not supported" error

[spicamelot]

Target SharePoint environment

SharePoint Online

What SharePoint development model, framework, SDK or API is this about?

💥 SharePoint Framework

Developer environment

None

What browser(s) / client(s) have you tested

• 💥 Internet Explorer
• 💥 Microsoft Edge
• 💥 Google Chrome
• 💥 FireFox
• 💥 Safari
• mobile (iOS/iPadOS)
• mobile (Android)
• not applicable
• other (enter in the "Additional environment details" area below)

Additional environment details

• Edge 140.0.3485.54
• Graph Explorer

Describe the bug / error

Granting an app read access to a sharepoint site works for sites, but not for subsites.

POST https://graph.microsoft.com/v1.0/sites//permissions works fine with real sites, but when the site target a child of the site, the API call returns a "notSupported" error.

The subsite does not inherit permissions from his parent site.

Steps to reproduce

1.Create a SharePoint site
2.Create a subsite with specific permissions
3.Register an Entra Application
4.Grant the application Sites.Selected permission
5.Connect to graph explorer with a your corporate account (https://developer.microsoft.com/en-us/graph/graph-explorer)
6.Get the full subsite id with graph explorer (https://graph.microsoft.com/v1.0/sites/subsite/sites?select=id,webUrl)
7.Post https://graph.microsoft.com/v1.0/sites//permissions the to Graph Explorer

Expected behavior

Returns an array of permissions

[Ashlesha-MSFT]

Hello @spicamelot,
Thank you for bringing this issue to our attention. We will look into it and get back to you shortly.
If you don’t receive a reply within two working days, please use this escalation form to escalate.

[Ashlesha-MSFT]

@spicamelot,

We were able to reproduce the issue, and we are investigating it. We have logged this as a bug, and our engineering team will look into it.