NULL Pointer Dereference in gpac/gpac


Reported on

Jan 18th 2022


Null Pointer Dereference in gf_dump_vrml_field.isra ()

Proof of Concept

MP4Box -bt POC2

POC2 is here.


Program received signal SIGSEGV, Segmentation fault.
0x0000000000644ca4 in gf_dump_vrml_field.isra ()
────────────────────────────────────────────────────────────────────────[ REGISTERS ]────────────────────────────────────────────────────────────────────────
 RAX  0x1
 RBX  0x1
 RCX  0x0
 RDX  0x0
 RDI  0xf3a100 ◂— 0x0
 RSI  0xc6a6e6 ◂— 0x7365445f5345005b /* '[' */
 R8   0x1
 R9   0x1
 R10  0xfffffff9
 R11  0xf392a0 ◂— 0x30646c6569665f /* '_field0' */
 R12  0x0
 R13  0xf38710 —▸ 0xf2d950 ◂— 0x0
 R14  0x0
 R15  0x3b
 RBP  0xf39960 —▸ 0xf399b0 ◂— 0x100010001
 RSP  0x7fffffff70c0 —▸ 0xf392a0 ◂— 0x30646c6569665f /* '_field0' */
 RIP  0x644ca4 (gf_dump_vrml_field.isra+1332) ◂— mov    edi, dword ptr [r12]
─────────────────────────────────────────────────────────────────────────[ DISASM ]──────────────────────────────────────────────────────────────────────────
 ► 0x644ca4 <gf_dump_vrml_field.isra+1332>    mov    edi, dword ptr [r12]
   0x644ca8 <gf_dump_vrml_field.isra+1336>    lea    rbx, [rsp + 0x20]
   0x644cad <gf_dump_vrml_field.isra+1341>    test   edi, edi
   0x644caf <gf_dump_vrml_field.isra+1343>    je     gf_dump_vrml_field.isra+1432                      <gf_dump_vrml_field.isra+1432>
   0x644d08 <gf_dump_vrml_field.isra+1432>    mov    esi, dword ptr [r13 + 0x30]
   0x644d0c <gf_dump_vrml_field.isra+1436>    mov    rdi, qword ptr [r13 + 0x10]
   0x644d10 <gf_dump_vrml_field.isra+1440>    test   esi, esi
   0x644d12 <gf_dump_vrml_field.isra+1442>    je     gf_dump_vrml_field.isra+1840                      <gf_dump_vrml_field.isra+1840>
   0x644ea0 <gf_dump_vrml_field.isra+1840>    xor    eax, eax
   0x644ea2 <gf_dump_vrml_field.isra+1842>    lea    rsi, [rip + 0x5f4fd3]
   0x644ea9 <gf_dump_vrml_field.isra+1849>    call   gf_fprintf                      <gf_fprintf>
──────────────────────────────────────────────────────────────────────────[ STACK ]──────────────────────────────────────────────────────────────────────────
00:0000rsp 0x7fffffff70c0 —▸ 0xf392a0 ◂— 0x30646c6569665f /* '_field0' */
01:00080x7fffffff70c8 ◂— 0x40b8270500000038 /* '8' */
02:00100x7fffffff70d0 —▸ 0xf3b210 ◂— 0x0
03:00180x7fffffff70d8 —▸ 0xf3b210 ◂— 0x0
04:00200x7fffffff70e0 —▸ 0xf387d0 —▸ 0xf37f10 ◂— 0x0
05:00280x7fffffff70e8 —▸ 0x7fffffff7114 ◂— 0xf38ab000000001
06:00300x7fffffff70f0 ◂— 0x0
07:00380x7fffffff70f8 ◂— 0x2
────────────────────────────────────────────────────────────────────────[ BACKTRACE ]────────────────────────────────────────────────────────────────────────
 ► f 0         0x644ca4 gf_dump_vrml_field.isra+1332
   f 1         0x6459ce gf_dump_vrml_node+1566
   f 2         0x642039 gf_sm_dump_command_list+873
   f 3         0x64908d gf_sm_dump+797
   f 4         0x41b5d8 dump_isom_scene+616
   f 5         0x4125ec mp4boxMain+9228
   f 6         0xb59600 __libc_start_main+1168

We are processing your report and will contact the gpac team within 24 hours. a year ago
We have contacted a member of the gpac team and are waiting to hear back a year ago
10 months ago


Hello, This bug seems to have been fixed on github, and the maintainer seems to have forgotten to click verify on huntr. Thank you.

We have sent a follow up to the gpac team. We will try again in 7 days. 10 months ago
gpac/gpac maintainer
10 months ago


That's correct, see

gpac/gpac maintainer validated this vulnerability 10 months ago
zfeixq has been awarded the disclosure bounty
The fix bounty is now up for grabs
gpac/gpac maintainer marked this as fixed in 1.1.0 with commit 9f8510 10 months ago
The fix bounty has been dropped
This vulnerability will not receive a CVE
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