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

App & System Services Networking Beta Xcode Network CFNetwork

Created Jun ’25

Replies 33

Boosts 25

Views 7.8k

Participants 23

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.

Answered by DTS Engineer in 855530022

Apple replied to my feedback that this got fixed in iOS 26 beta 4.

Yep. That matches my view of FB18043319.

If anyone is continuing to have problems with this, please reply here with the details.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

felixs OP

Jun ’25

The crash still occurs in Xcode 26 beta 2 under macOS Tahoe beta 2 here, too. A clean & build didn't resolve the issue, either.

I also couldn't find any mention of this issue in the release notes for Xcode 26 beta 2, so I assume it's still pending to be fixed.

RCP_at_Socure OP

Jun ’25

Like the others have noted, this is still an issue with Xcode 26 Beta 2 as well.

DTS Engineer OP

Apple

Jun ’25

this is still an issue with Xcode 26 Beta 2 as well.

Indeed.

For the record, the ‘lead bug’ here is FB18043319, and that’s not fixed in 26.0b2.

However, we do now fully understand the problem, so there’s no need for any more bug reports about this. Thanks to everyone who chipped in here.

I don’t have any info to share as to when this’ll be fixed. If this is causing you significant grief then I suggest that you temporarily apply the workaround suggested by salla.an in this post. I just happened to bump into this issue myself last week and that workaround got me past it.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

DTS Engineer OP

Apple

Jun ’25

Any chance you can un-accept the answer I accepted as correct … ?

A weird quirk of the DevForums platform is that it’s not possible to change an accepted answer, either as the original poster or an admin. Needless to say, I consider that to be a bug (r. 113568518).

I can change the Apple Recommended answer, and I’ll do that as this issue evolves.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

jeffctown OP

Jul ’25

My app ran into this error also. It was caused by the Datadog Static framework. Reporting that the nw_tls_create_options fix works for that too.

lazeebc OP

Jul ’25

Hi! What is the current status of the bug? We started hitting this on xcode 26 beta and seems like the workaround does not work for us - calling nw_tls_create_options() before URLSession calls. I dont see any notes about this in beta3 as well.

mgalijot OP

Aug ’25

Apple replied to my feedback that this got fixed in iOS 26 beta 4.

Anybody else still facing this crash on iOS 26 beta 4?

@DTS Engineer if the bug is fixed entirely, can you please comment about this bug resolution and make your comment "Apple Recommended"?

DTS Engineer OP

Apple

Aug ’25

Recommended

Apple replied to my feedback that this got fixed in iOS 26 beta 4.

Yep. That matches my view of FB18043319.

If anyone is continuing to have problems with this, please reply here with the details.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"