Crash in URLSessionConfiguration init in Xcode 26.0 beta (17A5241e)

It's not yet fully clear why and when does this crash occur, but I'm creating this post so there's a centralized thread for this.

Some hints collected so far:

• The crash is occurring for existing Xcode projects opened with new Xcode 26.0 beta (17A5241e); no one's been able to reproduce on a project created in Xcode 26. I even tried creating a project with Xcode 16.2 and open it in Xcode 26, but it's all working fine there (don't have older Xcode at the moment, to try with many versions)
• It crashes right at the line of code that initializes URLSessionConfiguration. If you call URLSession() without parameters (which is deprecated as of iOS 13), the session initializes without the crash.
• It's NOT occurring only for libraries installed through package manages. In a project where it crashes, one should be able to reproduce by adding URLSessionConfiguration.default as the first line in didFinishLaunchingWithOptions
• It crashes when running an app on an iOS 26 simulator. (I don't have a device running beta iOS 26 to test on it!) It's working fine when running the app on a simulator or a device running iOS 18 or older.

Related issue on Firebase GitHub repo: https://github.com/firebase/firebase-ios-sdk/issues/14948

Sorry to not be able to provide more info at the moment. I wanted to report this so in case someone from Apple knows about it, we could at least get some feedback or workarounds, until fix is released -- and, to prevent us all from duplicating this report in repositories of each library, as this isn't related to libraries.