## Description
There is a segment fault detected by AddressSanitizer

## System info
```
Ubuntu 20.04.2 LTS
clang version 12.0.0-++20210402082642+04ba60cfe598-1~exp1~20210402063359.71
MP4Box - GPAC version 1.1.0-DEV-rev1687-g16bd902cb-master
```

## Build command
```
./configure --static-mp4box --prefix=`realpath ./install` --enable-sanitizer --cc=clang --cxx=clang++
```

## crash command
```
MP4Box -isma -out /dev/null poc_file
```

## Pocs
[poc.zip](https://github.com/gpac/gpac/files/7976887/poc.zip)


## Crash output
```
==31085==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x0000008f9ad2 bp 0x7ffe1f847890 sp 0x7ffe1f8474a0 T0)
==31085==The signal is caused by a READ memory access.
==31085==Hint: address points to the zero page.
    #0 0x8f9ad2 in gf_media_make_isma /programs/mp4box/builds/build6/src/media_tools/isom_tools.c:591:66
    #1 0x4e4934 in mp4boxMain /programs/mp4box/builds/build6/applications/mp4box/main.c:6332:8
    #2 0x7f086dc130b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #3 0x41ea6d in _start (/programs/mp4box/builds/build6/bin/gcc/MP4Box+0x41ea6d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /programs/mp4box/builds/build6/src/media_tools/isom_tools.c:591:66 in gf_media_make_isma
==31085==ABORTING
/collect/collec.sh: line 18: 31085 Aborted (core dumped)
------------------------
```
There is a segment fault detected by AddressSanitizer
This is a GitHub Issue
repo:gpac
owner:gpac
Title : There is a segment fault detected by AddressSanitizer
Issue date:

--- start body ---
## Description
There is a segment fault detected by AddressSanitizer

## System info
```
Ubuntu 20.04.2 LTS
clang version 12.0.0-++20210402082642+04ba60cfe598-1~exp1~20210402063359.71
MP4Box - GPAC version 1.1.0-DEV-rev1687-g16bd902cb-master
```

## Build command
```
./configure --static-mp4box --prefix=`realpath ./install` --enable-sanitizer --cc=clang --cxx=clang++
```

## crash command
```
MP4Box -isma -out /dev/null poc_file
```

## Pocs
[poc.zip](https://github.com/gpac/gpac/files/7976887/poc.zip)


## Crash output
```
==31085==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x0000008f9ad2 bp 0x7ffe1f847890 sp 0x7ffe1f8474a0 T0)
==31085==The signal is caused by a READ memory access.
==31085==Hint: address points to the zero page.
    #0 0x8f9ad2 in gf_media_make_isma /programs/mp4box/builds/build6/src/media_tools/isom_tools.c:591:66
    #1 0x4e4934 in mp4boxMain /programs/mp4box/builds/build6/applications/mp4box/main.c:6332:8
    #2 0x7f086dc130b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #3 0x41ea6d in _start (/programs/mp4box/builds/build6/bin/gcc/MP4Box+0x41ea6d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /programs/mp4box/builds/build6/src/media_tools/isom_tools.c:591:66 in gf_media_make_isma
==31085==ABORTING
/collect/collec.sh: line 18: 31085 Aborted (core dumped)
------------------------
```
--- end body ---

A segmentation fault in the GPAC MP4Box application, specifically in the gf_media_make_isma function, indicates a potential vulnerability that could be exploited to cause a Denial of Service (DoS) by providing a specially crafted input file. The crash occurs due to a read access violation, which suggests that the application is attempting to access an invalid memory address.