Our business interface requests require disabling HTTP(s) proxies. We configured URLSessionConfiguration.connectionProxyDictionary as before, but found that it does not work on iOS 26 1.Core code: let configuration = URLSessionConfiguration.default configuration.connectionProxyDictionary = [ "HTTPEnable": false, "HTTPSEnable": false, "SOCKSEnable": false, ] let session = URLSession(configuration: configuration) let request = URLRequest(url: URL(string: "https://www.baidu.com")!,timeoutInterval: Double.infinity) // 发送请求 let task = session.dataTask(with: request) { data, response, error in if let error = error { print("网络请求失败: \(error)") } if let data = data { print("网络请求成功，返回数据长度: \(data.count)") if let responseString = String(data: data, encoding: .utf8) { print("返回数据: \(responseString.prefix(100))...") } } } task.resume() 2.Specific steps: We captured traffic using Proxyman and Charles. With the same code, requests cannot be captured on iOS 18 and iOS 16.1, but can be captured on iOS 26.2 and 26.1. Conclusion:Therefore, we suspect there is a bug with URLSessionConfiguration.connectionProxyDictionary on iOS 26.x. Please let us know whether this is a bug. If not, how should we properly disable HTTP(s) proxies? Note: We need to exclude PAC proxies, which are commonly used in corporate internal networks. 3.Devices & Software Xcode 16.4 iPhone 26.2、Simulator 26.1 iPhone 16、Simulator 18.0、Simulator 18.6 Proxyman、Charles

Some mobile phones frequently report an error "bad URL" with the domain set to NSURLErrorDomain and the code set to -1000. However, I never encounter this error, and I'm not sure what's going wrong，The error log is as follows: HttpInterceptor:81 didReceive(_:target:): moya error: underlying(Alamofire.AFError.sessionTaskFailed(error: Error Domain=NSURLErrorDomain Code=-1000 "bad URL" UserInfo={_kCFStreamErrorCodeKey=22, NSUnderlyingError=0x1119f91d0 {Error Domain=kCFErrorDomainCFNetwork Code=-1000 "(null)" UserInfo={_NSURLErrorNWPathKey=satisfied (Path is satisfied), interface: utun4[endc_sub6], ipv4, dns, uses cell, LQM: unknown, _kCFStreamErrorCodeKey=22, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <7FF86D00-1379-43D4-9F9B-0C300AEC57C8>.<4>, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <7FF86D00-1379-43D4-9F9B-0C300AEC57C8>.<4>" ), NSLocalizedDescription=bad URL, NSErrorFailingURLStringKey=https://update.flashforge.com/api/updates/check?app_id=46&entity_id=9E8D3B0C-2E61-46AF-91B9-B4AFFACF2788&platform=23&version=v1.3.4, NSErrorFailingURLKey=https://update.flashforge.com/api/updates/check?app_id=46&entity_id=9E8D3B0C-2E61-46AF-91B9-B4AFFACF2788&platform=23&version=v1.3.4, _kCFStreamErrorDomainKey=1}), nil)

According to documentation, the URLSession background tasks continue even when the app is suspended. What is the lifespan of the URLSessionDownloadDelegate object when app is suspended or terminated? Will it get re-created and re-initialize properties when the app re-launches, or will it somehow restore the existing property values? Also, urlSessionDidFinishEvents not getting called, and what do we need to do there with the backgroundCompletionHandler? Any insights are much appreciated. We are getting ready to launch and this is a roadblock. (visionOS26.4) Thank you. @Observable class DownloadManager: NSObject, URLSessionDownloadDelegate { ... let config = URLSessionConfiguration.background(withIdentifier: "TestDL") config.sessionSendsLaunchEvents = true var urlSession = URLSession(configuration: config, delegate: self, delegateQueue: nil) func downloadFiles(... { // initiate multiple file downloads concurrently for url in urlList { let task = urlSession.downloadTask(with: url) task.resume() } } func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) { ... func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) { ... func urlSession(_: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) { ... // Not getting called ?? // Is this only called when app is suspended/terminated? func urlSessionDidFinishEvents(forBackgroundURLSession session: URLSession) { print("didFinishEvents") Task { @MainActor in //urlSession?.finishTasksAndInvalidate() //urlSession = nil // not sure what to do here: if let appDelegate = UIApplication.shared.delegate as? AppDelegate, let completionHandler = appDelegate.backgroundCompletionHandler { completionHandler() appDelegate.backgroundCompletionHandler = nil } } }

Hello, I am investigating a recurring crash that appears to be originating within the system's network stack. OS Version: iPhone OS 26.1 (23B85) Role: Foreground Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000000 Exception Codes: 0x0000000000000001, 0x0000000000000000 Triggered by Thread: 19 Description: The crash is triggered by Thread 19 and occurs deep within libquic.dylib during a QUIC recovery timer event. Based on the backtrace, the failure happens in quic_recovery_pto. The issue seems to occur when a protocol instance schedules a wakeup, leading to a null pointer dereference in the system library. Crashed Thread Backtrace snippet:Thread 19 Crashed: Thread 19 Crashed: 0 libquic.dylib 0x00000001a00a38cc quic_recovery_pto + 72 (quic_recovery.c:1259) 1 libquic.dylib 0x00000001a00a3390 quic_recovery_timer_fired + 132 (quic_recovery.c:1460) 2 libquic.dylib 0x00000001a00a1f8c quic_timer_run + 248 (quic_timer.c:210) 3 Network 0x000000018ec76cbc __nw_protocol_instance_schedule_wakeup_block_invoke + 76 (protocol_implementation.cpp:5847) 4 Network 0x000000018eba34e0 __nw_context_reset_timer_block_with_time_block_invoke + 268 (context.cpp:2224) 5 libdispatch.dylib 0x00000001c84727ec _dispatch_client_callout + 16 (client_callout.mm:85) 6 libdispatch.dylib 0x00000001c845d664 _dispatch_continuation_pop + 596 (queue.c:349) 7 libdispatch.dylib 0x00000001c8470528 _dispatch_source_latch_and_call + 396 (source.c:601) 8 libdispatch.dylib 0x00000001c846f1fc _dispatch_source_invoke + 844 (source.c:966) 9 libdispatch.dylib 0x00000001c8463288 _dispatch_workloop_invoke + 1612 (queue.c:4761) 10 libdispatch.dylib 0x00000001c846c3ec _dispatch_root_queue_drain_deferred_wlh + 292 (queue.c:7265) 11 libdispatch.dylib 0x00000001c846bce4 _dispatch_workloop_worker_thread + 692 (queue.c:6859) 12 libsystem_pthread.dylib 0x00000001ec0623b8 _pthread_wqthread + 292 (pthread.c:2696) 13 libsystem_pthread.dylib 0x00000001ec0618c0 start_wqthread + 8 (:-1) Can anyone provide insights into what might be causing libquic to access an invalid address in this context? Any help or suggestions for further diagnostics would be greatly appreciated.

I'm keeping most information in an actor and I would like to save also a closure in it that I get from func application( _ application: UIApplication, handleEventsForBackgroundURLSession identifier: String, completionHandler: @escaping () -> Void) Task.init{ await GeoreferenceQueue.shared.setBackgroundCompletionHandler(completionHandler) } } where GeoreferenceQueue is and actor, while the caller is a class. yet I receive error: Passing closure as a 'sending' parameter risks causing data races between code in the current task and concurrent execution of the closure and Sending task-isolated 'completionHandler' to actor-isolated instance method 'setBackgroundCompletionHandler' risks causing data races between actor-isolated and task-isolated uses

Platform and Version Platform: iOS iOS Version: 17.0+ Development Environment: .NET MAUI (C#, .NET 9) Network Layer: HttpClient with HttpClientHandler Description of the Problem We are facing an issue where HttpClientHandler.ServerCertificateCustomValidationCallback is not being invoked when the app is in a terminated (kill) state. In normal app lifecycle states (foreground/background), the callback is triggered as expected and allows us to handle server certificate validation (e.g., for certificate pinning or custom validation logic). However, when the app is in a killed state and is relaunched due to a notification action, the callback does not execute. We would like to understand: Why ServerCertificateCustomValidationCallback is not invoked in this scenario Whether this behavior is expected within iOS networking/runtime constraints Any recommended approach or workaround to ensure certificate validation still occurs when handling notification-triggered flows from a terminated state Steps to Reproduce Ensure the app is force-terminated (kill mode) Configure a push notification with category: "INVITE_CATEGORY" Include custom notification action buttons Tap one of the custom actions This triggers app launch and network call using HttpClient Expected Behavior ServerCertificateCustomValidationCallback should be invoked during the network request initiated after tapping the notification action, allowing custom certificate validation.

libquic.dylib crashes with a null/invalid buffer access in nw_protocol_data_access_buffer during QUIC connection path migration on iOS 26. App code is not in the stack — this is entirely within Apple system libraries. We are seeing a consistent crash on iOS 26 that does not reproduce on iOS 17 or iOS 18. The crash occurs on a background thread ("com.apple.network.connections") with no application code in the crashed thread's stack. The crash trace begins in quic_migration_probe_path and terminates in nw_protocol_data_access_buffer + 180, suggesting a use-after-free or buffer lifetime violation during QUIC connection path migration (e.g., Wi-Fi ↔ Cellular handoff). This crash does not appear to be reproducible on demand — it correlates with network path transitions while QUIC connections are active. Our app uses standard URLSession with default/ephemeral session configurations and does not explicitly enable HTTP/3; iOS 26 is automatically upgrading eligible connections. Crash thread (abbreviated): 0 libquic.dylib quic_conn_send_packet + 144 1 libquic.dylib quic_conn_continue_sending + 424 2 libquic.dylib __quic_conn_send_frames_for_key_state_block_invoke_2 + 1244 3 Network nw_protocol_data_access_buffer + 180 ← crash 4 Network nw_protocol_data_copy_buffer 5 Network nw_endpoint_flow_output_frames 6 libquic.dylib quic_conn_send_frames_for_key_state 7 libquic.dylib quic_conn_send_frames 8 libquic.dylib quic_migration_probe_path + 1464 9 libquic.dylib quic_migration_path_established + 2608 10 libquic.dylib __quic_migration_path_event_block_invoke.21 11 libquic.dylib quic_migration_path_event 12 Network nw_protocol_implementation_connected There is no app code in the crashed thread. This is a regression introduced in iOS 26, where libquic.dylib was separated into its own dynamic library and new path migration probe logic was introduced.

We are seeing a consistent crash on iOS 26 that does not reproduce on iOS 17 or iOS 18. The crash occurs on a background thread ("com.apple.network.connections") with no application code in the crashed thread's stack. The crash trace begins in quic_migration_probe_path and terminates in nw_protocol_data_access_buffer + 180, suggesting a use-after-free or buffer lifetime violation during QUIC connection path migration (e.g., Wi-Fi ↔ Cellular handoff). This crash does not appear to be reproducible on demand — it correlates with network path transitions while QUIC connections are active. Our app uses standard URLSession with default/ephemeral session configurations and does not explicitly enable HTTP/3; iOS 26 is automatically upgrading eligible connections. Crash thread (abbreviated): 0 libquic.dylib quic_conn_send_packet + 144 1 libquic.dylib quic_conn_continue_sending + 424 2 libquic.dylib __quic_conn_send_frames_for_key_state_block_invoke_2 + 1244 3 Network nw_protocol_data_access_buffer + 180 ← crash 4 Network nw_protocol_data_copy_buffer 5 Network nw_endpoint_flow_output_frames 6 libquic.dylib quic_conn_send_frames_for_key_state 7 libquic.dylib quic_conn_send_frames 8 libquic.dylib quic_migration_probe_path + 1464 9 libquic.dylib quic_migration_path_established + 2608 10 libquic.dylib __quic_migration_path_event_block_invoke.21 11 libquic.dylib quic_migration_path_event 12 Network nw_protocol_implementation_connected There is no app code in the crashed thread. This is a regression introduced in iOS 26, where libquic.dylib was separated into its own dynamic library and new path migration probe logic was introduced. iOS → iOS 26 Networking → URLSession / Network.framework

We develop a healthcare emergency-alerting app with a native watchOS companion app. We've hit a network routing issue on watchOS that we cannot work around with any public API, and it breaks a safety-critical flow (triggering an emergency alarm from the watch). Environment watchOS 26.5 on Apple Watch SE3, paired with iPhone SE on iOS 26.5 Watch app deployment target: watchOS 9.0 Plain URLSession (async/await), default configuration plus waitsForConnectivity = false, allowsExpensiveNetworkAccess = true, allowsConstrainedNetworkAccess = true HTTPS to our own backend (valid public TLS certificate, no pinning) Steps to reproduce Pair the watch with the iPhone. Both on the same known Wi-Fi network. On the iPhone: turn OFF Wi-Fi and cellular data. Keep Bluetooth ON. The watch remains connected to its known Wi-Fi network (or would be, if the system brought the radio up). Trigger any HTTPS request from the watch app (foreground). Expected Since the companion iPhone has no internet, the watch should satisfy the request over its own Wi-Fi. Actual The request is routed through the companion link (ipsec1, "companion preference: prefer" in the logs) and fails after the TLS handshake dies inside the tunnel: Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." _kCFStreamErrorDomainKey=3, _kCFStreamErrorCodeKey=-9816 (errSSLClosedNoNotify) The watch never fails over to its own Wi-Fi, no matter how many times we retry or how long we wait. The same request succeeds within seconds if the user disables Bluetooth on the iPhone (watch then joins Wi-Fi directly), or restores the iPhone's internet. What we already tried waitsForConnectivity = true doesn't help; a path exists (the tunnel), it just doesn't work. Fresh URLSession per retry, backoff retries still routed via the tunnel. Per TN3135 we understand low-level networking is not available to a normal app: we prototyped NWConnection with prohibitedInterfaceTypes = [.other], and indeed on device NWPathMonitor stays .unsatisfied even when the watch has working Wi-Fi, exactly as TN3135 describes. So Network framework is not an escape hatch for us, and we are not looking to abuse the audio-streaming/CallKit carve-outs. Questions Is the companion-preferred routing supposed to fail over to the watch's own Wi-Fi when the iPhone is reachable over Bluetooth but has no internet? If yes, on what timescale, and is there anything an app can do to help the system notice the dead path sooner? Is there ANY supported way for a foreground watchOS app to express "do not use the companion link for this request"? We found only the private _companionProxyPreference SPI, which we obviously can't ship. If the answer to both is "no", what is the recommended pattern for safety-critical requests in this state is failing fast and instructing the user to disable iPhone Bluetooth really the intended UX? Related earlier reports of the same behavior: https://developer.apple.com/forums/thread/759321 https://developer.apple.com/forums/thread/107964

We develop a healthcare emergency-alerting app with a native watchOS companion app. We've hit a network routing issue on watchOS that we cannot work around with any public API, and it breaks a safety-critical flow (triggering an emergency alarm from the watch). Environment watchOS 26.5 on Apple Watch SE3, paired with iPhone SE 2nd Gen on iOS 26.5 Watch app deployment target: watchOS 9.0 Plain URLSession (async/await), default configuration plus waitsForConnectivity = false, allowsExpensiveNetworkAccess = true, allowsConstrainedNetworkAccess = true HTTPS to our own backend (valid public TLS certificate, no pinning) Steps to reproduce Pair the watch with the iPhone. Both on the same known Wi-Fi network. On the iPhone: turn OFF Wi-Fi and cellular data. Keep Bluetooth ON. The watch remains connected to its known Wi-Fi network (or would be, if the system brought the radio up). Trigger any HTTPS request from the watch app (foreground). Expected Since the companion iPhone has no internet, the watch should satisfy the request over its own Wi-Fi. Actual The request is routed through the companion link (ipsec1, "companion preference: prefer" in the logs) and fails after the TLS handshake dies inside the tunnel: Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." _kCFStreamErrorDomainKey=3, _kCFStreamErrorCodeKey=-9816 (errSSLClosedNoNotify) The watch never fails over to its own Wi-Fi, no matter how many times we retry or how long we wait. The same request succeeds within seconds if the user disables Bluetooth on the iPhone (watch then joins Wi-Fi directly), or restores the iPhone's internet. What we already tried waitsForConnectivity = true doesn't help; a path exists (the tunnel), it just doesn't work. Fresh URLSession per retry, backoff retries still routed via the tunnel. Per TN3135 we understand low-level networking is not available to a normal app: we prototyped NWConnection with prohibitedInterfaceTypes = [.other], and indeed on device NWPathMonitor stays .unsatisfied even when the watch has working Wi-Fi, exactly as TN3135 describes. So Network framework is not an escape hatch for us, and we are not looking to abuse the audio-streaming/CallKit carve-outs. Questions Is the companion-preferred routing supposed to fail over to the watch's own Wi-Fi when the iPhone is reachable over Bluetooth but has no internet? If yes, on what timescale, and is there anything an app can do to help the system notice the dead path sooner? Is there ANY supported way for a foreground watchOS app to express "do not use the companion link for this request"? We found only the private _companionProxyPreference SPI, which we obviously can't ship. If the answer to both is "no", what is the recommended pattern for safety-critical requests in this state is failing fast and instructing the user to disable iPhone Bluetooth really the intended UX? Related earlier reports of the same behavior: https://developer.apple.com/forums/thread/759321 https://developer.apple.com/forums/thread/107964

When my URLSessionDelegate receives a server trust challenge (NSURLAuthenticationMethodServerTrust) and I respond with .useCredential for an enterprise self-signed cert, does the decision get cached for subsequent requests on the same URLSession, or is the delegate called again on every connection to the same host?

Is the system default for this still false as of the OS 27 releases? When would you recommend setting it to true?

Hello, Our app makes a lot of requests and we are starting to wrangle them into a priority queue style structure for ordered execution. As we get further into that work, is there guidance on how many requests URLSession will queue and does that change based on connectivity or network quality? Thank you!

Hello, We recently moved to the NWPath.Status implementation for reachability, is that the same reachability that powers URLSessionConfiguration.waitsForConnectivity? Or does the NWPath implementation rely on a specific network path such as cell only or wifi only? Is using NWPath still the best way to measure if the network is reachable? Thank you!