[Crashlytics] EXC_GUARD crash with "Additional Runtime Platform Restrictions" enabled (iOS 26.1)

[sidbmw]

Description

[Crashlytics] EXC_GUARD crash with "Additional Runtime Platform Restrictions" enabled (iOS 26.1)

Issue Description

Firebase Crashlytics causes immediate app crash on iOS 26 due to EXC_GUARD exception when attempting to register mach port exception handlers. This occurs when "Enable Additional Runtime Platform Restrictions" is enabled under Enhanced Security → Runtime Protections.

Environment

• iOS Version: iOS 26.1 beta 2
• Firebase iOS SDK Version: 12.4.0
• Xcode Version: 26.0.1
• Device: Physical iPhone running iOS 26.1 beta 2
• Deployment Target: iOS 26.0

Stack Trace

Exception Type: EXC_GUARD
Exception Subtype: GUARD_TYPE_MACH_PORT
Exception Message: SET_EXCEPTION_BEHAVIOR on mach port 2147483649

Thread 1 Crashed:
0   libsystem_kernel.dylib         mach_port_set_attributes
1   FirebaseCrashlytics            FIRCLSMachExceptionRegister
2   FirebaseCrashlytics            FIRCLSMachExceptionInit
3   FirebaseCrashlytics            FIRCLSContext
4   FirebaseCrashlytics            -[FIRCLSInternalReport initWithPath:executionIdentifier:]

Steps to Reproduce

1. Create new Xcode 26.0.1 project targeting iOS 26.0+
2. Add Firebase iOS SDK 12.4.0 with Crashlytics
3. In project settings, go to Signing & Capabilities → Enhanced Security → Runtime Protections
4. Enable "Enable Additional Runtime Platform Restrictions" (this adds the com.apple.security.hardened-process.platform-restrictions entitlement)
5. Build and run on physical device with iOS 26.1 beta 2
6. App crashes immediately on launch with EXC_GUARD exception

Expected Behavior

App should launch successfully with Crashlytics enabled, compatible with iOS 26's Runtime Platform Restrictions which protect against attacks on the dynamic loader and Mach messaging.

Actual Behavior

App crashes with EXC_GUARD exception because the "Additional Runtime Platform Restrictions" setting blocks mach port exception handler registration that Crashlytics requires.

Temporary Workaround

Disable "Additional Runtime Platform Restrictions" in Xcode:

1. Go to project settings → Signing & Capabilities → Enhanced Security → Runtime Protections
2. Uncheck "Enable Additional Runtime Platform Restrictions"

Or manually remove the entitlement from your .entitlements file:

<!-- Remove this key -->
<key>com.apple.security.hardened-process.platform-restrictions</key>
<true/>

This allows the app to run but sacrifices protection against dynamic loader and Mach messaging attacks. Other Enhanced Security features (Typed Allocator, Read-only Platform Memory, etc.) can remain enabled.

Additional Context

• This only affects iOS 26+ with "Additional Runtime Platform Restrictions" specifically enabled
• Other Enhanced Security features work fine (Typed Allocator, Read-only Platform Memory, Hardware Memory Tagging)
• Works on iOS 26.1 beta 2 when "Additional Runtime Platform Restrictions" is disabled
• The platform restrictions setting protects against "attacks on the dynamic loader and Mach messaging" (per Apple's description)
• Crashlytics uses mach port exception handlers (mach_port_set_attributes with SET_EXCEPTION_BEHAVIOR)
• Other Firebase services (Auth, Firestore, Analytics, Functions, Performance) work correctly with all Enhanced Security features
• Tested with Firebase SDK 12.4.0 (latest as of October 2025)

Request

Please update Firebase Crashlytics to be compatible with iOS 26's "Additional Runtime Platform Restrictions", either by:

1. Using alternative crash reporting mechanisms that don't require mach port exception handlers
2. Detecting the platform-restrictions entitlement and gracefully degrading functionality
3. Providing guidance on proper iOS 26 integration with full Enhanced Security enabled

Related Issues

• Apple's iOS 26 introduced enhanced restrictions on mach port operations for security
• Enhanced App Protection with platform-restrictions is recommended for iOS 26+ apps
• This is currently blocking production deployment with full iOS 26 security hardening

---

Is this blocking production deployment? Yes - cannot ship apps with "Additional Runtime Platform Restrictions" enabled on iOS 26, which forces us to disable protection against dynamic loader and Mach messaging attacks.

Reproducing the issue

No response

Firebase SDK Version

12.4

Xcode Version

26.0.1

Installation Method

Swift Package Manager

Firebase Product(s)

Crashlytics, App Check, Firestore, Functions, Authentication

Targeted Platforms

iOS

Relevant Log Output

If using Swift Package Manager, the project's Package.resolved

Expand Package.resolved snippet

{
  "originHash" : "c63c63846d9c539229e96de38d6af51417e28c0ee9a0bc48bd0f0f19d923c329",
  "pins" : [
    {
      "identity" : "abseil-cpp-binary",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/abseil-cpp-binary.git",
      "state" : {
        "revision" : "bbe8b69694d7873315fd3a4ad41efe043e1c07c5",
        "version" : "1.2024072200.0"
      }
    },
    {
      "identity" : "app-check",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/app-check.git",
      "state" : {
        "revision" : "61b85103a1aeed8218f17c794687781505fbbef5",
        "version" : "11.2.0"
      }
    },
    {
      "identity" : "firebase-ios-sdk",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/firebase-ios-sdk",
      "state" : {
        "revision" : "541ac342abead313f2ce0ccf33278962b5c1e43c",
        "version" : "12.4.0"
      }
    },
    {
      "identity" : "google-ads-on-device-conversion-ios-sdk",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/googleads/google-ads-on-device-conversion-ios-sdk",
      "state" : {
        "revision" : "2ba031f43ef88a7f6631c84d23794eb99751e891",
        "version" : "3.1.0"
      }
    },
    {
      "identity" : "googleappmeasurement",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleAppMeasurement.git",
      "state" : {
        "revision" : "52713644ce2831bb687ded4aefd5e5c9f15565c5",
        "version" : "12.4.0"
      }
    },
    {
      "identity" : "googledatatransport",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleDataTransport.git",
      "state" : {
        "revision" : "617af071af9aa1d6a091d59a202910ac482128f9",
        "version" : "10.1.0"
      }
    },
    {
      "identity" : "googleutilities",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleUtilities.git",
      "state" : {
        "revision" : "60da361632d0de02786f709bdc0c4df340f7613e",
        "version" : "8.1.0"
      }
    },
    {
      "identity" : "grpc-binary",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/grpc-binary.git",
      "state" : {
        "revision" : "75b31c842f664a0f46a2e590a570e370249fd8f6",
        "version" : "1.69.1"
      }
    },
    {
      "identity" : "gtm-session-fetcher",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/gtm-session-fetcher.git",
      "state" : {
        "revision" : "c756a29784521063b6a1202907e2cc47f41b667c",
        "version" : "4.5.0"
      }
    },
    {
      "identity" : "interop-ios-for-google-sdks",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/interop-ios-for-google-sdks.git",
      "state" : {
        "revision" : "040d087ac2267d2ddd4cca36c757d1c6a05fdbfe",
        "version" : "101.0.0"
      }
    },
    {
      "identity" : "leveldb",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/leveldb.git",
      "state" : {
        "revision" : "a0bc79961d7be727d258d33d5a6b2f1023270ba1",
        "version" : "1.22.5"
      }
    },
    {
      "identity" : "nanopb",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/nanopb.git",
      "state" : {
        "revision" : "b7e1104502eca3a213b46303391ca4d3bc8ddec1",
        "version" : "2.30910.0"
      }
    },
    {
      "identity" : "promises",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/promises.git",
      "state" : {
        "revision" : "540318ecedd63d883069ae7f1ed811a2df00b6ac",
        "version" : "2.4.0"
      }
    },
    {
      "identity" : "swift-protobuf",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/apple/swift-protobuf.git",
      "state" : {
        "revision" : "2547102afd04fe49f1b286090f13ebce07284980",
        "version" : "1.31.1"
      }
    }
  ],
  "version" : 3
}

If using CocoaPods, the project's Podfile.lock

Expand Podfile.lock snippet

Replace this line with the contents of your Podfile.lock!

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[rizafran]

Thanks for reporting, @sidbmw. I'm unable to reproduce the issue though I'm using a simulator. I believe that this is only reproducible in physical device which might be related to issue #15008.

[sidbmw]

Thanks for reporting, @sidbmw. I'm unable to reproduce the issue though I'm using a simulator. I believe that this is only reproducible in physical device which might be related to issue #15008.

One thing to note btw is that on first build/run from xcode onto a physical device it runs just fine. Once you kill the connection and just launch the app on that same device, it will crash instantaneously. I can't repro on a simulator either (which might be a simulator bug now that i think about it as it should be "identical" to a physical device)

[rizafran]

Thanks for the additional info. Please add a 👍 to the original issue so the engineers could help them prioritize it.

[JesusRojass]

Hello there @sidbmw

I am taking a look into this!

Wondering if this is also happening on the beta 3 of iOS 26.1?

[sidbmw]

Hello there @sidbmw

I am taking a look into this!

Wondering if this is also happening on the beta 3 of iOS 26.1?

I haven't given it a try yet but will do so on a bit!

[JesusRojass]

Sounds good either way apple still signs the beta 2 so I am also downgrading to check and see, maybe if you dont want to upgrade just yet so I can check with my physical device first

[sidbmw]

Sounds good either way apple still signs the beta 2 so I am also downgrading to check and see, maybe if you dont want to upgrade just yet so I can check with my physical device first

My phone is on beta 3 already haha. I don't mind checking on beta 3. Just gotta eat lunch and finish a couple other tasks with my app before I can dive into this. I should be to let you know if it still crashes within the hour

[JesusRojass]

awesome!
dont rush I will be here trying your steps!

thank you for the patience on this!

[sidbmw]

awesome!
dont rush I will be here trying your steps!

thank you for the patience on this!

Yep crashes in beta 3 as well

[JesusRojass]

Not good but thanks for the confirmation!

Will come back to you in a bit I also debugging this on my end!

[JesusRojass]

@sidbmw good news I am seeing what you are seeing and I'm able to replicate

Looking at what could be the root cause!! :D

hang tight, we will fix this!