We have a SAML-based SSO App Extension that uses WKWebView to load the SAML login request. This implementation has been working correctly on iOS versions prior to 26. However, starting with iOS 26, the extension consistently crashes when calling WKWebView.load(_:).
The crash occurs inside WebKit, specifically in:
/Library/Caches/com.apple.xbs/Sources/WebKit/Source/WebKit/UIProcess/WebsiteData/WebsiteDataStore.cpp
at
WebKit::WebPageProxy::loadRequest(...)
No app-level exception is thrown, and the extension terminates with:
Thread 10: EXC_BREAKPOINT (code=1, subcode=0x1a31dbe00)
It appears that WKWebView initialization or WebsiteDataStore creation is now restricted in extension contexts on iOS 26, but this change is not documented in the SDK release notes. Could you please confirm if this is an intentional sandbox restriction in iOS 26 or a regression in WebKit?
Steps to reproduce:
Implement an App Extension using ASAuthorizationProviderExtensionAuthorizationRequest.
Create a WKWebView instance in the extension.
Attempt to load a SAML login request (POST request with headers).
Observe immediate crash on iOS 26 (works fine on earlier versions).
Expected behavior:
WKWebView should load the request or fail gracefully as in prior releases, without crashing the extension process.
Request:
Please clarify if WKWebView usage inside extensions is officially unsupported as of iOS 26, and if so, recommend an alternative approach for handling SSO flows.