Heap corruption in `read_bitstream`

[libumem]

• Version: 0.3.0.0
• OS: Debian 12
• Command: ./oapv_app_dec -i ./poc_au_size_overflow.apv -m 1 -v 0

Attached is a zip with the file needed to reproduce this.

ASAN Trace

=================================================================
==44434==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x73a3139ff800 at pc 0x5d6de0a14ac3 bp 0x7ffe52fcbcf0 sp 0x7ffe52fcbce8
WRITE of size 1 at 0x73a3139ff800 thread T0
    #0 0x5d6de0a14ac2 in read_bitstream <removed>/app/oapv_app_dec.c:198:35
    #1 0x5d6de0a11ba1 in main <removed>/app/oapv_app_dec.c:502:21
    #2 0x73a31617d249 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #3 0x73a31617d304 in __libc_start_main csu/../csu/libc-start.c:360:3
    #4 0x5d6de0950420 in _start (<removed>/build/bin/oapv_app_dec+0x51420) (BuildId: 56db50aa25683e3033552d96267c16b1450aad86)

0x73a3139ff800 is located 0 bytes to the right of 134217728-byte region [0x73a30b9ff800,0x73a3139ff800)
allocated by thread T0 here:
    #0 0x5d6de09d326e in __interceptor_malloc (<removed>/build/bin/oapv_app_dec+0xd426e) (BuildId: 56db50aa25683e3033552d96267c16b1450aad86)
    #1 0x5d6de0a118c6 in main <removed>/app/oapv_app_dec.c:464:14
    #2 0x73a31617d249 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16

SUMMARY: AddressSanitizer: heap-buffer-overflow <removed>/app/oapv_app_dec.c:198:35 in read_bitstream
Shadow bytes around the buggy address:
  0x0e74e2737eb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0e74e2737ec0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0e74e2737ed0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0e74e2737ee0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0e74e2737ef0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0e74e2737f00:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0e74e2737f10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0e74e2737f20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0e74e2737f30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0e74e2737f40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0e74e2737f50: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==44434==ABORTING

poc.zip