Hello, In our app, we used NSStream for several years but most of them were used to open HTTP sockets. Since we started using it for HTTPS sockets we have regularly a few (but not insignificant) crashes linked apparently to SSL writing: It happens when the NSStreamDelegate receive a "NSStreamEventHasSpaceAvailable" event in the method "(void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)streamEvent". When this event is received, we do a "[outputStream write:data maxLength:size];" then it crashes Here are the information found in one of the crash logs: Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Subtype: KERN_INVALID_ADDRESS at 0x000000015488bd98 Exception Codes: 0x0000000000000001, 0x000000015488bd98 VM Region Info: 0x15488bd98 is not in any region. Bytes after previous region: 1621401 Bytes before following region: 6767208 REGION TYPE START - END [ VSIZE] PRT/MAX SHRMOD REGION DETAIL MALLOC_TINY 154600000-154700000 [ 1024K] rw-/rwx SM=PRV ---> GAP OF 0x800000 BYTES MALLOC_LARGE 154f00000-154f84000 [ 528K] rw-/rwx SM=PRV Exception Note: EXC_CORPSE_NOTIFY Terminating Process: exc handler [430] Triggered by Thread: 17 Thread 17 Crashed: 0 libsystem_platform.dylib 0x00000001f12d5ae0 _platform_memmove + 144 1 libcoretls.dylib 0x00000001f020841c tls_record_encrypt + 580 (tls_record.c:320) 2 Security 0x00000001894d1e98 SSLRecordWriteInternal + 112 (SSLRecordInternal.c:230) 3 Security 0x00000001894d2d68 SSLWrite + 236 (sslRecord.c:87) 4 CFNetwork 0x00000001810345c0 SocketStream::write(__CFWriteStream*, unsigned char const*, long, CFStreamError*) + 804 (SocketStream.cpp:7824) 5 CoreFoundation 0x00000001806cc254 CFWriteStreamWrite + 452 (CFStream.c:1242) Thread 17 crashed with ARM Thread State (64-bit): x0: 0x0000000150849225 x1: 0x000000015488bd98 x2: 0x0000000000001000 x3: 0x0000000150849240 x4: 0x0000000004042b73 x5: 0x00000000000000e0 x6: 0x00000000000000eb x7: 0x00000002807a6a40 x8: 0x000000000000000d x9: 0x000000016c7fd4d7 x10: 0x0000000000000000 x11: 0x0000000000000000 x12: 0x0000000000000000 x13: 0x00000000ffff8015 x14: 0x0000000000000211 x15: 0x000000000000a81e x16: 0x00000001f12d5a50 x17: 0x00000002063d9398 x18: 0x0000000000000000 x19: 0x0000000000001018 x20: 0x0000000150849225 x21: 0x0000000000000002 x22: 0x0000000000001000 x23: 0x0000000152111d90 x24: 0x0000000000000001 x25: 0x000000000000101d x26: 0x0000000000001000 x27: 0x000000000000101d x28: 0x0000000000000010 fp: 0x000000016c7fd540 lr: 0x00000001f020841c sp: 0x000000016c7fd480 pc: 0x00000001f12d5ae0 cpsr: 0x80001000 esr: 0x92000007 (Data Abort) byte read Translation fault Any idea of what should be the problem and how we can avoid these crashes ? Many thanks in advance.