We are also seeing this reported to crashlytics and currently only happening on iOS 7 devices. When it happens, we also have an AFNetworking thread up.
From this SO thread, we found that setting the cache to zero seemed to eliminate the crash but this is not a permanent solution.
NSURLCache *sharedCache = [[NSURLCache alloc] initWithMemoryCapacity:0
diskCapacity:0
diskPath:nil];
[NSURLCache setSharedURLCache:sharedCache];
We have some other NSURLCache code that we think is suspect that we are currently testing out, I will keep you updated.
UPDATE
We seemed to have resolved the issue. What we believe solved the crash was code that was clobbering the [NSURLCache sharedURLCache]
when another part of code was using it. We removed all calls that modify [NSURLCache sharedURLCache]
.