Hello,I use the fuzzer(AFL) to fuzz binary gpac and got some crashes.
The following is the details.

Title:SEGV on unknown address 0x000000000000
### Description

A SEGV on unknown address 0x000000000000 has occurred in function mp4box_main /gpac/applications/mp4box/mp4box.c:6786:7
when running program MP4Box, this can reproduce on the lattest commit.

### Software&&System version info

```
$ ./MP4Box -version
MP4Box - GPAC version 2.3-DEV-rev389-g6ae306f5a-master
(c) 2000-2023 Telecom Paris distributed under LGPL v2.1+ - http://gpac.io
 $uname -a
Linux ppg-X10DRi 5.11.0-49-generic #55-Ubuntu SMP Wed Jan 12 17:36:34 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
```

### Steps to reproduce
```
CFLAGS="-g -O0 -lpthread -fsanitize=address"  ./configure
make -j
```

### Command&&Result

```
$./MP4Box -add poc1 -new /tmp/output.mp4 -frag 5000
[iso file] Incomplete box mdat - start 11977 size 276821
[iso file] Incomplete file while reading for dump - aborting parsing
IsoMedia import 00 - track ID 201 - Video (size 176 x 144)
IsoMedia import 00 - track ID 65737 - media type "hint:rtp "
IsoMedia import 00 - track ID 101 - Audio (SR 11025 - 1 channels)
IsoMedia import 00 - track ID 65637 - media type "hint:rtp "
Fragmenting file (5.000 seconds fragments)
AddressSanitizer:DEADLYSIGNAL
=================================================================
==3203904==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f9c110243dc bp 0x607000007090 sp 0x7ffc316eb230 T0)
==3203904==The signal is caused by a READ memory access.
==3203904==Hint: address points to the zero page.
    #0 0x7f9c110243dc in gf_isom_add_user_data (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x39a3dc)
    #1 0x7f9c11585a69 in mp4_mux_set_udta (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x8fba69)
    #2 0x7f9c1157f480 in mp4_mux_setup_pid (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x8f5480)
    #3 0x7f9c11396030 in gf_filter_pid_configure (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x70c030)
    #4 0x7f9c113a4ad6 in gf_filter_pid_connect_task (/home/ppg/fuzzgpac/build_carpet/lib/libgpac.so.12+0x71aad6)
    #5 0x7f9c113cfa94 in gf_fs_thread_proc (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x745a94)
    #6 0x7f9c113ce9a0 in gf_fs_run (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x7449a0)
    #7 0x7f9c110c5743 in gf_media_fragment_file (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x43b743)
    #8 0x4ec3c6 in mp4box_main /home/ppg/fuzz/gpac/applications/mp4box/mp4box.c:6786:7
    #9 0x7f9c10918564 in __libc_start_main csu/../csu/libc-start.c:332:16
    #10 0x42ad1d in _start (/home/ppg/fuzz/gpac/build_carpet/bin/MP4Box+0x42ad1d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x39a3dc) in gf_isom_add_user_data
==3203904==ABORTING
```

### Impact

This vulnerability is capable of crashing software, Bypass Protection Mechanism, Modify Memory, and possible remote execution.

###  POC
[poc1.zip](https://github.com/gpac/gpac/files/11889188/poc1.zip)


SEGV on unknown address 0x000000000000
This is a GitHub Issue
repo:gpac
owner:gpac
Title : SEGV on unknown address 0x000000000000
Issue date:

--- start body ---
Hello,I use the fuzzer(AFL) to fuzz binary gpac and got some crashes.
The following is the details.

Title:SEGV on unknown address 0x000000000000
### Description

A SEGV on unknown address 0x000000000000 has occurred in function mp4box_main /gpac/applications/mp4box/mp4box.c:6786:7
when running program MP4Box, this can reproduce on the lattest commit.

### Software&&System version info

```
$ ./MP4Box -version
MP4Box - GPAC version 2.3-DEV-rev389-g6ae306f5a-master
(c) 2000-2023 Telecom Paris distributed under LGPL v2.1+ - http://gpac.io
 $uname -a
Linux ppg-X10DRi 5.11.0-49-generic #55-Ubuntu SMP Wed Jan 12 17:36:34 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
```

### Steps to reproduce
```
CFLAGS="-g -O0 -lpthread -fsanitize=address"  ./configure
make -j
```

### Command&&Result

```
$./MP4Box -add poc1 -new /tmp/output.mp4 -frag 5000
[iso file] Incomplete box mdat - start 11977 size 276821
[iso file] Incomplete file while reading for dump - aborting parsing
IsoMedia import 00 - track ID 201 - Video (size 176 x 144)
IsoMedia import 00 - track ID 65737 - media type "hint:rtp "
IsoMedia import 00 - track ID 101 - Audio (SR 11025 - 1 channels)
IsoMedia import 00 - track ID 65637 - media type "hint:rtp "
Fragmenting file (5.000 seconds fragments)
AddressSanitizer:DEADLYSIGNAL
=================================================================
==3203904==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f9c110243dc bp 0x607000007090 sp 0x7ffc316eb230 T0)
==3203904==The signal is caused by a READ memory access.
==3203904==Hint: address points to the zero page.
    #0 0x7f9c110243dc in gf_isom_add_user_data (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x39a3dc)
    #1 0x7f9c11585a69 in mp4_mux_set_udta (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x8fba69)
    #2 0x7f9c1157f480 in mp4_mux_setup_pid (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x8f5480)
    #3 0x7f9c11396030 in gf_filter_pid_configure (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x70c030)
    #4 0x7f9c113a4ad6 in gf_filter_pid_connect_task (/home/ppg/fuzzgpac/build_carpet/lib/libgpac.so.12+0x71aad6)
    #5 0x7f9c113cfa94 in gf_fs_thread_proc (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x745a94)
    #6 0x7f9c113ce9a0 in gf_fs_run (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x7449a0)
    #7 0x7f9c110c5743 in gf_media_fragment_file (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x43b743)
    #8 0x4ec3c6 in mp4box_main /home/ppg/fuzz/gpac/applications/mp4box/mp4box.c:6786:7
    #9 0x7f9c10918564 in __libc_start_main csu/../csu/libc-start.c:332:16
    #10 0x42ad1d in _start (/home/ppg/fuzz/gpac/build_carpet/bin/MP4Box+0x42ad1d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/home/ppg/fuzz/gpac/build_carpet/lib/libgpac.so.12+0x39a3dc) in gf_isom_add_user_data
==3203904==ABORTING
```

### Impact

This vulnerability is capable of crashing software, Bypass Protection Mechanism, Modify Memory, and possible remote execution.

###  POC
[poc1.zip](https://github.com/gpac/gpac/files/11889188/poc1.zip)


--- end body ---
