iOS 26: EXC_BAD_ACCESS crash in SentrySDKInternal startWithOptions when _experiments is set

[maaz-coros]

What React Native libraries do you use?

Expo Application Services (EAS)

Are you using sentry.io or on-premise?

sentry.io (SaS)

Are you using any other error monitoring solution alongside Sentry?

No

Other Error Monitoring Solution Name

No response

@sentry/react-native SDK Version

8.8.0

How does your development environment look like?

  react-native: 0.81.5
  expo: ~54.0.0                                                                 
  react: 19.1.0   
  OS: iPhone OS 26.3.1 (23D771330a)
  Device: iPhone 14 (iPhone14,5)   
  Distribution: TestFlight (EAS Build)

Sentry.init()

  Sentry.init({   
    dsn: process.env.EXPO_PUBLIC_SENTRY_DSN,                                    
    integrations: [], // mobileReplayIntegration excluded on iOS
    tracesSampleRate: 1.0,                                      
    _experiments: { profilesSampleRate: 1.0 },                                  
    enabled: true,                            
    debug: false,                                                               
  });

Steps to Reproduce

1. Build iOS using EAS Build with profile targeting iOS 26 device
2. Install via TestFlight on iPhone running iOS 26.3.1
3. Launch the app
4. App crashes immediately before any screen renders

Expected Result

App launches successfully, Sentry initializes without crashing.

Actual Result

App crashes immediately on launch with EXC_BAD_ACCESS (SIGSEGV).
KERN_INVALID_ADDRESS at 0x0000000000000010

Crash trace:
0 +[SentrySDKInternal startWithOptions:] + 436 (SentrySDKInternal.m:236)
1 specialized static SentrySDK.start(options:) + 516 (SentrySDK.swift:105)
2 +[RNSentryStart startWithOptions:] + 136 (RNSentryStart.m:29)
3 -[RNSentry initNativeSdk:resolve:rejecter:] + 112 (RNSentry.mm:148)

Session Replay is already disabled on iOS (mobileReplayIntegration not used).
Suspected trigger: _experiments: { profilesSampleRate: 1.0 }.
Removing _experiments stops the crash.

[linear-code]

RN-590

[antonis]

Thank you for reporting 🙇 We will investigate this and iterate back.

[antonis]

@maaz-coros We were not able to reproduce the reported behavior. Please note that using the profilesSampleRate outside the _experiments (see docs) should solve this for you.
If the issue persists could you please share the full crash log 🙇

[maaz-coros]

Hi, apologies for the confusion on this one — after further investigation, the root cause of the crash was actually a typo in our Sentry DSN configuration (a stray space in the URL that caused a null pointer dereference in the native Cocoa SDK during initialization). This was a mistake on our end, not a Sentry SDK bug.

Thanks for the prompt response and for maintaining such a great SDK. Closing this issue.