An invalid memory address dereference vulnerability exists in gpac 1.1.0 via the svg_node_start function, which causes a segmentation fault and application crash.
Thanks for reporting your issue. Please make sure these boxes are checked before submitting your issue - thank you!

- [x] I looked for a similar issue and couldn't find any.
- [x] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
- [x] I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...). I can share files anonymously with this dropbox: https://www.mediafire.com/filedrop/filedrop_hosted.php?drop=eec9e058a9486fe4e99c33021481d9e1826ca9dbc242a6cfaab0fe95da5e5d95

Detailed guidelines: http://gpac.io/2013/07/16/how-to-file-a-bug-properly/

An invalid memory address dereference was discovered in svg_node_start(). The vulnerability causes a segmentation fault and application crash.

**Version:**

```
MP4Box - GPAC version 1.1.0-DEV-revUNKNOWN_REV
(c) 2000-2021 Telecom Paris distributed under LGPL v2.1+ - http://gpac.io

Please cite our work in your research:
        GPAC Filters: https://doi.org/10.1145/3339825.3394929
        GPAC: https://doi.org/10.1145/1291233.1291452

GPAC Configuration:
Features: GPAC_CONFIG_LINUX GPAC_64_BITS GPAC_HAS_IPV6 GPAC_HAS_SOCK_UN GPAC_MINIMAL_ODF GPAC_HAS_QJS GPAC_HAS_JPEG GPAC_HAS_PNG GPAC_HAS_LINUX_DVB  GPAC_DISABLE_3D
```
**System information**
Ubuntu 20.04 focal, AMD EPYC 7742 64-Core @ 16x 2.25GHz

**command:**

```
./MP4Box -lsr poc_2.xsr
```
[poc_2.zip](https://github.com/gpac/gpac/files/7692197/poc_2.zip)

**Result**

```
[Parser] LASeR Scene Parsing: ./poc/poc_2.xsr
[1]    75845 segmentation fault  ./MP4Box -lsr ./poc/poc_2.xsr
```

**gdb**

```
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7aa5f97 in svg_node_start () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
────────────────────────────────────────────[ REGISTERS ]─────────────────────────────────────────────
 RAX  0x0
 RBX  0x5555555c7750 ◂— 0x0
 RCX  0x0
 RDX  0x5555555ce2b0 —▸ 0x5555555ce0e3 ◂— 0x7572742200706172 /* 'rap' */
 RDI  0x7ffff7e447c9 ◂— 'Unable to parse chunk: %s'
 RSI  0x5555555ce0e3 ◂— 0x7572742200706172 /* 'rap' */
 R8   0x7fffffff5c3c ◂— 0x0
 R9   0x5555555ce0e3 ◂— 0x7572742200706172 /* 'rap' */
 R10  0x0
 R11  0x0
 R12  0x5555555ce2b0 —▸ 0x5555555ce0e3 ◂— 0x7572742200706172 /* 'rap' */
 R13  0x5555555ce0d5 ◂— 0x6e65637300666173 /* 'saf' */
 R14  0x1
 R15  0x0
 RBP  0x5555555cf390 —▸ 0x7fffffff7310 ◂— 0x7
 RSP  0x7fffffff5bb0 ◂— 0x0
 RIP  0x7ffff7aa5f97 (svg_node_start+3095) ◂— mov    rdi, qword ptr [rax + 0x20]
──────────────────────────────────────────────[ DISASM ]──────────────────────────────────────────────
 ► 0x7ffff7aa5f97 <svg_node_start+3095>    mov    rdi, qword ptr [rax + 0x20]
   0x7ffff7aa5f9b <svg_node_start+3099>    call   gf_list_count@plt                <gf_list_count@plt>

   0x7ffff7aa5fa0 <svg_node_start+3104>    test   eax, eax
   0x7ffff7aa5fa2 <svg_node_start+3106>    sete   r15b
   0x7ffff7aa5fa6 <svg_node_start+3110>    test   r14d, r14d
   0x7ffff7aa5fa9 <svg_node_start+3113>    jne    svg_node_start+6240                <svg_node_start+6240>

   0x7ffff7aa5faf <svg_node_start+3119>    xor    esi, esi
   0x7ffff7aa5fb1 <svg_node_start+3121>    nop    dword ptr [rax]
   0x7ffff7aa5fb8 <svg_node_start+3128>    mov    rdi, qword ptr [rbp + 0x50]
   0x7ffff7aa5fbc <svg_node_start+3132>    mov    edx, r15d
   0x7ffff7aa5fbf <svg_node_start+3135>    pxor   xmm0, xmm0
──────────────────────────────────────────────[ STACK ]───────────────────────────────────────────────
00:0000│ rsp 0x7fffffff5bb0 ◂— 0x0
01:0008│     0x7fffffff5bb8 —▸ 0x5555555ce0d9 ◂— 'sceneUnit'
02:0010│     0x7fffffff5bc0 ◂— 0x0
03:0018│     0x7fffffff5bc8 ◂— 0x0
04:0020│     0x7fffffff5bd0 —▸ 0x5555555ce0d5 ◂— 0x6e65637300666173 /* 'saf' */
05:0028│     0x7fffffff5bd8 ◂— 0x0
06:0030│     0x7fffffff5be0 ◂— 0x0
07:0038│     0x7fffffff5be8 ◂— 0x3000000020 /* ' ' */
────────────────────────────────────────────[ BACKTRACE ]─────────────────────────────────────────────
 ► f 0   0x7ffff7aa5f97 svg_node_start+3095
   f 1   0x7ffff781fbc5 xml_sax_node_start+453
   f 2   0x7ffff7820e6c xml_sax_parse+3596
   f 3   0x7ffff78213d6 gf_xml_sax_parse_intern+950
   f 4   0x7ffff7821595 gf_xml_sax_parse+165
   f 5   0x7ffff7821633 xml_sax_read_file.part+115
   f 6   0x7ffff7821927 gf_xml_sax_parse_file+295
   f 7   0x7ffff7aa42da load_svg_run+58
──────────────────────────────────────────────────────────────────────────────────────────────────────
pwndbg> bt
#0  0x00007ffff7aa5f97 in svg_node_start () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#1  0x00007ffff781fbc5 in xml_sax_node_start () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#2  0x00007ffff7820e6c in xml_sax_parse () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#3  0x00007ffff78213d6 in gf_xml_sax_parse_intern () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#4  0x00007ffff7821595 in gf_xml_sax_parse () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#5  0x00007ffff7821633 in xml_sax_read_file.part () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#6  0x00007ffff7821927 in gf_xml_sax_parse_file () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#7  0x00007ffff7aa42da in load_svg_run () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#8  0x00005555555844a8 in dump_isom_scene ()
#9  0x000055555557b42c in mp4boxMain ()
#10 0x00007ffff75630b3 in __libc_start_main (main=0x55555556c420 <main>, argc=3, argv=0x7fffffffe188, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe178) at ../csu/libc-start.c:308
#11 0x000055555556c45e in _start ()
```


Invalid memory address dereference in svg_node_start()
This is a GitHub Issue
repo:gpac
owner:gpac
Title : Invalid memory address dereference in svg_node_start()
Issue date:

--- start body ---
Thanks for reporting your issue. Please make sure these boxes are checked before submitting your issue - thank you!

- [x] I looked for a similar issue and couldn't find any.
- [x] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
- [x] I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...). I can share files anonymously with this dropbox: https://www.mediafire.com/filedrop/filedrop_hosted.php?drop=eec9e058a9486fe4e99c33021481d9e1826ca9dbc242a6cfaab0fe95da5e5d95

Detailed guidelines: http://gpac.io/2013/07/16/how-to-file-a-bug-properly/

An invalid memory address dereference was discovered in svg_node_start(). The vulnerability causes a segmentation fault and application crash.

**Version:**

```
MP4Box - GPAC version 1.1.0-DEV-revUNKNOWN_REV
(c) 2000-2021 Telecom Paris distributed under LGPL v2.1+ - http://gpac.io

Please cite our work in your research:
        GPAC Filters: https://doi.org/10.1145/3339825.3394929
        GPAC: https://doi.org/10.1145/1291233.1291452

GPAC Configuration:
Features: GPAC_CONFIG_LINUX GPAC_64_BITS GPAC_HAS_IPV6 GPAC_HAS_SOCK_UN GPAC_MINIMAL_ODF GPAC_HAS_QJS GPAC_HAS_JPEG GPAC_HAS_PNG GPAC_HAS_LINUX_DVB  GPAC_DISABLE_3D
```
**System information**
Ubuntu 20.04 focal, AMD EPYC 7742 64-Core @ 16x 2.25GHz

**command:**

```
./MP4Box -lsr poc_2.xsr
```
[poc_2.zip](https://github.com/gpac/gpac/files/7692197/poc_2.zip)

**Result**

```
[Parser] LASeR Scene Parsing: ./poc/poc_2.xsr
[1]    75845 segmentation fault  ./MP4Box -lsr ./poc/poc_2.xsr
```

**gdb**

```
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7aa5f97 in svg_node_start () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
LEGEND: STACK | HEAP | CODE | DATA | RWX | RODATA
────────────────────────────────────────────[ REGISTERS ]─────────────────────────────────────────────
 RAX  0x0
 RBX  0x5555555c7750 ◂— 0x0
 RCX  0x0
 RDX  0x5555555ce2b0 —▸ 0x5555555ce0e3 ◂— 0x7572742200706172 /* 'rap' */
 RDI  0x7ffff7e447c9 ◂— 'Unable to parse chunk: %s'
 RSI  0x5555555ce0e3 ◂— 0x7572742200706172 /* 'rap' */
 R8   0x7fffffff5c3c ◂— 0x0
 R9   0x5555555ce0e3 ◂— 0x7572742200706172 /* 'rap' */
 R10  0x0
 R11  0x0
 R12  0x5555555ce2b0 —▸ 0x5555555ce0e3 ◂— 0x7572742200706172 /* 'rap' */
 R13  0x5555555ce0d5 ◂— 0x6e65637300666173 /* 'saf' */
 R14  0x1
 R15  0x0
 RBP  0x5555555cf390 —▸ 0x7fffffff7310 ◂— 0x7
 RSP  0x7fffffff5bb0 ◂— 0x0
 RIP  0x7ffff7aa5f97 (svg_node_start+3095) ◂— mov    rdi, qword ptr [rax + 0x20]
──────────────────────────────────────────────[ DISASM ]──────────────────────────────────────────────
 ► 0x7ffff7aa5f97 <svg_node_start+3095>    mov    rdi, qword ptr [rax + 0x20]
   0x7ffff7aa5f9b <svg_node_start+3099>    call   gf_list_count@plt                <gf_list_count@plt>

   0x7ffff7aa5fa0 <svg_node_start+3104>    test   eax, eax
   0x7ffff7aa5fa2 <svg_node_start+3106>    sete   r15b
   0x7ffff7aa5fa6 <svg_node_start+3110>    test   r14d, r14d
   0x7ffff7aa5fa9 <svg_node_start+3113>    jne    svg_node_start+6240                <svg_node_start+6240>

   0x7ffff7aa5faf <svg_node_start+3119>    xor    esi, esi
   0x7ffff7aa5fb1 <svg_node_start+3121>    nop    dword ptr [rax]
   0x7ffff7aa5fb8 <svg_node_start+3128>    mov    rdi, qword ptr [rbp + 0x50]
   0x7ffff7aa5fbc <svg_node_start+3132>    mov    edx, r15d
   0x7ffff7aa5fbf <svg_node_start+3135>    pxor   xmm0, xmm0
──────────────────────────────────────────────[ STACK ]───────────────────────────────────────────────
00:0000│ rsp 0x7fffffff5bb0 ◂— 0x0
01:0008│     0x7fffffff5bb8 —▸ 0x5555555ce0d9 ◂— 'sceneUnit'
02:0010│     0x7fffffff5bc0 ◂— 0x0
03:0018│     0x7fffffff5bc8 ◂— 0x0
04:0020│     0x7fffffff5bd0 —▸ 0x5555555ce0d5 ◂— 0x6e65637300666173 /* 'saf' */
05:0028│     0x7fffffff5bd8 ◂— 0x0
06:0030│     0x7fffffff5be0 ◂— 0x0
07:0038│     0x7fffffff5be8 ◂— 0x3000000020 /* ' ' */
────────────────────────────────────────────[ BACKTRACE ]─────────────────────────────────────────────
 ► f 0   0x7ffff7aa5f97 svg_node_start+3095
   f 1   0x7ffff781fbc5 xml_sax_node_start+453
   f 2   0x7ffff7820e6c xml_sax_parse+3596
   f 3   0x7ffff78213d6 gf_xml_sax_parse_intern+950
   f 4   0x7ffff7821595 gf_xml_sax_parse+165
   f 5   0x7ffff7821633 xml_sax_read_file.part+115
   f 6   0x7ffff7821927 gf_xml_sax_parse_file+295
   f 7   0x7ffff7aa42da load_svg_run+58
──────────────────────────────────────────────────────────────────────────────────────────────────────
pwndbg> bt
#0  0x00007ffff7aa5f97 in svg_node_start () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#1  0x00007ffff781fbc5 in xml_sax_node_start () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#2  0x00007ffff7820e6c in xml_sax_parse () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#3  0x00007ffff78213d6 in gf_xml_sax_parse_intern () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#4  0x00007ffff7821595 in gf_xml_sax_parse () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#5  0x00007ffff7821633 in xml_sax_read_file.part () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#6  0x00007ffff7821927 in gf_xml_sax_parse_file () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#7  0x00007ffff7aa42da in load_svg_run () from /root/fuckit/test/gpac1210/bin/gcc/libgpac.so.10
#8  0x00005555555844a8 in dump_isom_scene ()
#9  0x000055555557b42c in mp4boxMain ()
#10 0x00007ffff75630b3 in __libc_start_main (main=0x55555556c420 <main>, argc=3, argv=0x7fffffffe188, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe178) at ../csu/libc-start.c:308
#11 0x000055555556c45e in _start ()
```


--- end body ---

An invalid memory address dereference in the svg_node_start() function of GPAC version 1.1.0-DEV can lead to a segmentation fault, causing the application to crash. This vulnerability can be exploited by providing a specially crafted SVG file, resulting in a Denial of Service (DoS).