Title / Summary
Crash in libquic.dylib when app is backgrounded and issues an HTTP/3 request
Description
On iOS 26, the app crashes inside libquic.dylib while performing a network request using HTTP/3 (QUIC) after the app has moved to the background. The crash happens within low-level QUIC / libquic internals.
Reproduction Steps
- Launch the app, perform normal operations.
- Background the app (press home / switch away).
- While in background, trigger a network request that uses HTTP/3 / QUIC.
- Observe that the app crashes (stack trace pointing into libquic.dylib).
Expected Behavior
The HTTP/3 request in background should either be handled gracefully (fail or complete) without causing a crash; the app must not be terminated due to internal libquic failures.
Actual Behavior
The app crashes with signals/exceptions coming from libquic.dylib (in the QUIC / packet building / encryption / key state logic) when a HTTP/3 request is made in background.
Environment / Device Information
• OS: iOS 26
• Device: iPhone 13 Pro Max
• Network environment: (Wi-Fi / Cellular)
• HTTP/3 support: enabled in URLSession / Network framework
Stack Trace：
Thanks for the crash report.
We collected the crash logs from users online.
So, does that mean that you can’t reproduce this yourself? Because in your original post you had “Reproduction Steps”, which suggests that this is something you can reproduce.
Based on thread 8, it looks like you’re using a third-party crash reporter. That makes things difficult, as I explain in Implementing Your Own Crash Reporter. My advice is that you remove this crash reporter from your app and try to get a Apple crash report for this crash.
Still, it’s probably worthwhile filing a bug with the info that you currently have. Please do that, and then post your bug number here.
Share and Enjoy
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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
