Ming (aka libming) 0.4.8 has an out of bounds read vulnerability in the function OpCode() in the decompile.c file in libutil.a.
# Description
An out of bound read was found in function OpCode(file util/decompile.c 957).

# Details:

```
==30829==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61400000f5d0 at pc 0x000000413ddb bp 0x7ffeb39e6460 sp 0x7ffeb39e6450
READ of size 1 at 0x61400000f5d0 thread T0
    #0 0x413dda in OpCode /src/libming-afl/util/decompile.c:957
    #1 0x415ab5 in decompileGETTIME /src/libming-afl/util/decompile.c:1506
    #2 0x41ecc9 in decompileAction /src/libming-afl/util/decompile.c:3264
    #3 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #4 0x41e83c in decompileSETTARGET /src/libming-afl/util/decompile.c:3169
    #5 0x41f292 in decompileAction /src/libming-afl/util/decompile.c:3462
    #6 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #7 0x419908 in decompileIF /src/libming-afl/util/decompile.c:2364
    #8 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #9 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #10 0x41b85b in decompileIF /src/libming-afl/util/decompile.c:2656
    #11 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #12 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #13 0x41b85b in decompileIF /src/libming-afl/util/decompile.c:2656
    #14 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #15 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #16 0x41b85b in decompileIF /src/libming-afl/util/decompile.c:2656
    #17 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #18 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #19 0x41b85b in decompileIF /src/libming-afl/util/decompile.c:2656
    #20 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #21 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #22 0x41f4b3 in decompile5Action /src/libming-afl/util/decompile.c:3517
    #23 0x40bb42 in outputSWF_DOACTION /src/libming-afl/util/outputscript.c:1551
    #24 0x40e171 in outputBlock /src/libming-afl/util/outputscript.c:2083
    #25 0x40f1c7 in readMovie /src/libming-afl/util/main.c:281
    #26 0x40f8fc in main /src/libming-afl/util/main.c:354
    #27 0x7f51e85bd82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #28 0x401998 in _start (/src/fuzz/swftocxx+0x401998)

0x61400000f5d0 is located 0 bytes to the right of 400-byte region [0x61400000f440,0x61400000f5d0)
allocated by thread T0 here:
    #0 0x7f51e8f2279a in __interceptor_calloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x9879a)
    #1 0x42854e in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1062
    #2 0x4289b2 in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1075
    #3 0x4289b2 in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1075
    #4 0x4289b2 in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1075
    #5 0x4289b2 in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1075
    #6 0x437ca5 in parseSWF_DOACTION /src/libming-afl/util/parser.c:2434
    #7 0x40fb59 in blockParse /src/libming-afl/util/blocktypes.c:145
    #8 0x40f116 in readMovie /src/libming-afl/util/main.c:269
    #9 0x40f8fc in main /src/libming-afl/util/main.c:354
    #10 0x7f51e85bd82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)

SUMMARY: AddressSanitizer: heap-buffer-overflow /src/libming-afl/util/decompile.c:957 OpCode
Shadow bytes around the buggy address:
  0x0c287fff9e60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c287fff9e70: 00 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa
  0x0c287fff9e80: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c287fff9e90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c287fff9ea0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c287fff9eb0: 00 00 00 00 00 00 00 00 00 00[fa]fa fa fa fa fa
  0x0c287fff9ec0: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
  0x0c287fff9ed0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c287fff9ee0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c287fff9ef0: fd fd fd fd fd fd fd fd fd fd fa fa fa fa fa fa
  0x0c287fff9f00: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
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
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  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
==30829==ABORTING
```
# poc file
https://github.com/JsHuang/pocs/blob/master/libming/swftocxx/oob_read_decompile_957

# Credit
ADLab of Venustech
Heap Buffer Overflow (OOB Read) in function OpCode decompile.c 957
This is a GitHub Issue
repo:libming
owner:libming
Title : Heap Buffer Overflow (OOB Read) in function OpCode decompile.c 957
Issue date:

--- start body ---
# Description
An out of bound read was found in function OpCode(file util/decompile.c 957).

# Details:

```
==30829==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61400000f5d0 at pc 0x000000413ddb bp 0x7ffeb39e6460 sp 0x7ffeb39e6450
READ of size 1 at 0x61400000f5d0 thread T0
    #0 0x413dda in OpCode /src/libming-afl/util/decompile.c:957
    #1 0x415ab5 in decompileGETTIME /src/libming-afl/util/decompile.c:1506
    #2 0x41ecc9 in decompileAction /src/libming-afl/util/decompile.c:3264
    #3 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #4 0x41e83c in decompileSETTARGET /src/libming-afl/util/decompile.c:3169
    #5 0x41f292 in decompileAction /src/libming-afl/util/decompile.c:3462
    #6 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #7 0x419908 in decompileIF /src/libming-afl/util/decompile.c:2364
    #8 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #9 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #10 0x41b85b in decompileIF /src/libming-afl/util/decompile.c:2656
    #11 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #12 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #13 0x41b85b in decompileIF /src/libming-afl/util/decompile.c:2656
    #14 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #15 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #16 0x41b85b in decompileIF /src/libming-afl/util/decompile.c:2656
    #17 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #18 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #19 0x41b85b in decompileIF /src/libming-afl/util/decompile.c:2656
    #20 0x41eef2 in decompileAction /src/libming-afl/util/decompile.c:3335
    #21 0x41f37d in decompileActions /src/libming-afl/util/decompile.c:3494
    #22 0x41f4b3 in decompile5Action /src/libming-afl/util/decompile.c:3517
    #23 0x40bb42 in outputSWF_DOACTION /src/libming-afl/util/outputscript.c:1551
    #24 0x40e171 in outputBlock /src/libming-afl/util/outputscript.c:2083
    #25 0x40f1c7 in readMovie /src/libming-afl/util/main.c:281
    #26 0x40f8fc in main /src/libming-afl/util/main.c:354
    #27 0x7f51e85bd82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #28 0x401998 in _start (/src/fuzz/swftocxx+0x401998)

0x61400000f5d0 is located 0 bytes to the right of 400-byte region [0x61400000f440,0x61400000f5d0)
allocated by thread T0 here:
    #0 0x7f51e8f2279a in __interceptor_calloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x9879a)
    #1 0x42854e in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1062
    #2 0x4289b2 in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1075
    #3 0x4289b2 in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1075
    #4 0x4289b2 in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1075
    #5 0x4289b2 in parseSWF_ACTIONRECORD /src/libming-afl/util/parser.c:1075
    #6 0x437ca5 in parseSWF_DOACTION /src/libming-afl/util/parser.c:2434
    #7 0x40fb59 in blockParse /src/libming-afl/util/blocktypes.c:145
    #8 0x40f116 in readMovie /src/libming-afl/util/main.c:269
    #9 0x40f8fc in main /src/libming-afl/util/main.c:354
    #10 0x7f51e85bd82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)

SUMMARY: AddressSanitizer: heap-buffer-overflow /src/libming-afl/util/decompile.c:957 OpCode
Shadow bytes around the buggy address:
  0x0c287fff9e60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c287fff9e70: 00 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa
  0x0c287fff9e80: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c287fff9e90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c287fff9ea0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c287fff9eb0: 00 00 00 00 00 00 00 00 00 00[fa]fa fa fa fa fa
  0x0c287fff9ec0: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
  0x0c287fff9ed0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c287fff9ee0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c287fff9ef0: fd fd fd fd fd fd fd fd fd fd fa fa fa fa fa fa
  0x0c287fff9f00: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
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
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  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
==30829==ABORTING
```
# poc file
https://github.com/JsHuang/pocs/blob/master/libming/swftocxx/oob_read_decompile_957

# Credit
ADLab of Venustech
--- end body ---

A heap buffer overflow vulnerability exists in the OpCode function of libming, specifically at line 957 of decompile.c. This vulnerability can be exploited to read beyond the allocated memory, potentially leading to information disclosure or application crashes. The issue is triggered when certain SWF files are processed, as demonstrated in the provided PoC file.