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： 8eedc0df3d914b0faf8def9af3b21574-symbolicated.crash

I was exploring the scenarios where an NWListener or NWConnection can be invalidated or reclaimed by the OS itself. I came across the document TN2277: Networking and Multitasking, which discusses situations where iOS can reclaim the underlying socket descriptor. The document states: while the app is suspended the system may choose to reclaim resources out from underneath a network socket used by the app, thereby closing the network connection represented by that socket. From this, I understand that when the app is in a suspended state, the OS may reclaim the socket descriptor. My questions are: In what scenarios does the OS not reclaim the socket descriptor while the app is suspended, and in which cases does it reclaim it? When reclamation occurs, does the OS reclaim 'a' single NWListener/NWConnection, or does it reclaim 'all' NWListener/NWConnections opened by the application? Thanks.

For testing purposes we have code that calls SecTrustEvaluateAsyncWithError() with a trust object containing a hardcoded leaf certificate and the corresponding intermediate certificate required to form a valid chain. Because the leaf certificate has since expired we pass a date in the past via SecTrustSetVerifyDate() at wich the certificate was still valid, but trust evaluation fails: Error Domain=NSOSStatusErrorDomain Code=-67825 "“<redacted>” certificate is not standards compliant" UserInfo={NSLocalizedDescription=“<redacted>” certificate is not standards compliant, NSUnderlyingError=0x600000c282a0 {Error Domain=NSOSStatusErrorDomain Code=-67825 "Certificate 0 “<redacted>” has errors: Certificate Transparency validation required for this use;" UserInfo={NSLocalizedDescription=Certificate 0 “<redacted>” has errors: Certificate Transparency validation required for this use;}}} I know that App Transport Security enforces Certificate Transparency by default, but is there a way around that here?

Hi Everyone, I have a query regarding capturing an NWConnection instance inside the receive closure, which gets invoked whenever some raw bytes are received. I want to know whether this will create a strong retain cycle or not. My understanding is that NWConnection holds a reference to the closure, and if I capture the NWConnection instance inside the closure, the closure will have a reference back to the connection, which, according to my understanding, creates a strong reference cycle. Is my understanding correct? If so, how can we break the strong reference cycle — using a capture list, or is there any other way as well? Thanks

Hi, Since iOS 26 (and any other apple system with a 26 version) there is a very weird behavior in the whole apple ecosystem (iOS, iPadOS, macOS and visionOS). I'm self-hosting a web project called mempool (https://github.com/Retropex/mempool). This project is entirely self-hosted on my own infrastructure, so I have advanced control to be sure it's just not an anti-DDoS feature that makes the bug happen. So the bug is once I visit my website, for example this page (https://mempool.guide/tx/d86192252a6631831e55f814aea901e65407b6dbda77e1abdea8ec27861e9682) the OS will lose the ability to connect to the underlying IP of the domain (mempool.guide) but the issue seems to affect only the HTTPS/HTTP port (443/80). The issue is system wide, not only is Safari. For exemple I have another domain that resolve to the same IP (haf.ovh) and if this link above trigger the bug then I will also lose the ability to connect to https://haf.ovh A temporary fix that I have is that if I turn off wifi/cellular then I turn it on again I can connect again to my server again until the bug is triggered again. I have done test with tcpdump on my server and the connection isn't making it to my server that's why I think it's an OS issue, especially given the fix above. This issue can be reproduced on any apple device out of the box with a system with >v26. All device (Mac, iPad, iPhone, vision) with version pre-26 are completely unaffected by the bug and can freely explore the website without loosing the connection macOS is less affected by this bug, it can be random with it. With iOS/iPadOS it's systematic. Another thing to note is that the same URL on firefox/chrome for iOS doesn't trigger the bug. Let me know if anyone has an idea on what's going on. Thanks, Léo.

Hi Apple Engineers and fellow developers, I'm a student developer working on an educational focus management app that helps users hide distracting apps during study sessions. The app consists of: macOS app: Simple "Hide apps" button that triggers app hidding sessions iOS app: Uses Screen Time API to temporarily hide selected apps from home screen Communication: Bonjour networking between Mac and iPhone for session coordination The Challenge My app requires two entitlements that aren't available with Personal Developer Teams: com.apple.developer.family-controls (for Screen Time API) com.apple.developer.networking.multicast (for Bonjour device discovery) Current Error Messages text Cannot create a iOS App Development provisioning profile for "focuser.focuser-app". Personal development teams, including "My Name", do not support the Family Controls (Development) capability. Provisioning profile doesn't include the com.apple.developer.family-controls and com.apple.developer.networking.multicast entitlements. My Question for Apple Engineers Is there any legitimate way to test these privacy-sensitive APIs on my own devices for educational/learning purposes without purchasing the $99/year Apple Developer Program membership? I understand the security reasons behind these restrictions, but as a student just learning iOS development, it creates a significant barrier to experimenting with these technologies.

Reproduce Same SIM card with 4G, same testing location, connected to the same server, xcode debugging game applications, network/profile retrotransmitted, Avg round trip to view data iPhone17， Turn off 4G and turn on WiFi. All the above indicators are acceptable iPhone17， Turn on 4G, turn off WiFi, retry with retransmission and very high Avg round trip iPhone14-16， Turn on 4G and turn off WiFi. All the above indicators are acceptable App Unity3d project .netframe4.0 C# Socket Other Many developers in Chinese forums have provided feedback on this issue

We have observed a per-process limitation on the number of simultaneous nw_connection_t objects in certain macOS environments. On some systems, this limit does not appear to apply, but on others the limitation is reproducible. When a process attempts to establish a large number of connections (e.g. 512+), some connections enter the nw_connection_state_waiting state and report the POSIX error “Cannot allocate memory”. These connections remain stuck indefinitely, even after other connections are deallocated and resources should theoretically be available again. This behavior severely impacts use cases such as transparent proxies implemented via the NetworkExtension framework, which intercept system-wide traffic and must open connections on behalf of all client processes. In this scenario, a per-process limit effectively becomes a system-wide limit, leading to unexpected and hard-to-diagnose network failures in client applications. So, is there any way to disable this restriction for Network Extension processes? Are there any system settings that could affect this limitation and be modified by users?

Enabling Private Relay seems to block XHR in Safari from reaching a local HTTPS server hosted by an iOS app, though it works in other browsers. Before (working): JS → https://local.example.com → 127.0.0.1 → OK After (blocked / no DNS reply probably): JS → https://local.example.com → ERR Is there any way to restore local domain access or mitigate this issue?

I have some confusion around the usage of DeviceDiscoveryUI. The documentation suggests that it is available only on TVOS. But with the recent announcement of WifiAware, it has been used in iOS devices as well. Within DeviceDiscoveryUI, the DevicePicker or the DevicePairingView documentation seems to be available with iOS. Is this just a documentation mistake? Followup - Can I use DeviceDiscoveryUI's DevicePicker/ DevicePairingView to discover devices through Bonjour and then establish a connection through Network framework?