Heap-based Buffer Overflow in function ins_compl_infercase_gettext() in vim/vim


Reported on

Jul 15th 2022


Heap-based Buffer Overflow in function ins_compl_infercase_gettext at src/insexpand.c:645

vim version

commit 3a393790a4fd7a5edcafbb55cd79438b6e641714
Author: Dominique Pelle <dominique.pelle@gmail.com>
Date:   Thu Jul 14 17:40:49 2022 +0100

    patch 9.0.0053: E1281 not tested with the old regexp engine
    Problem:    E1281 not tested with the old regexp engine.
    Solution:   Loop over the values of 'regexp'. (Dominique Pellé, closes #10695)

To reproduce

export CFLAGS="-g3 -fsanitize=address -fno-common -fno-omit-frame-pointer -fPIC"
export LDFLAGS="-g3 -fsanitize=address -fno-common -fno-omit-frame-pointer -fPIC"
make -j4
./src/vim -u NONE -i NONE -n -m -X -Z -e -s -S ./poc_hbor4_s.dat -c :qa!

Stack information

==33751==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x619000000981 at pc 0x7fa2ab4b7fe4 bp 0x7ffe8d066220 sp 0x7ffe8d0659c8
READ of size 1026 at 0x619000000981 thread T0
    #0 0x7fa2ab4b7fe3  (/usr/lib64/libasan.so.6+0x52fe3)
    #1 0x66cbdb in ins_compl_infercase_gettext /root/github_vim/src/insexpand.c:645
    #2 0x66d350 in ins_compl_add_infercase /root/github_vim/src/insexpand.c:725
    #3 0x6796d9 in get_next_default_completion /root/github_vim/src/insexpand.c:3668
    #4 0x6799db in get_next_completion_match /root/github_vim/src/insexpand.c:3733
    #5 0x679e91 in ins_compl_get_exp /root/github_vim/src/insexpand.c:3806
    #6 0x67aafa in find_next_completion_match /root/github_vim/src/insexpand.c:4041
    #7 0x67ae9e in ins_compl_next /root/github_vim/src/insexpand.c:4142
    #8 0x67e01c in ins_complete /root/github_vim/src/insexpand.c:4993
    #9 0x4d8fb4 in edit /root/github_vim/src/edit.c:1281
    #10 0x75c69a in op_change /root/github_vim/src/ops.c:1758
    #11 0x76e7ed in do_pending_operator /root/github_vim/src/ops.c:4041
    #12 0x724e12 in normal_cmd /root/github_vim/src/normal.c:961
    #13 0x5a98ab in exec_normal /root/github_vim/src/ex_docmd.c:8814
    #14 0x5a9674 in exec_normal_cmd /root/github_vim/src/ex_docmd.c:8777
    #15 0x5a8f0b in ex_normal /root/github_vim/src/ex_docmd.c:8695
    #16 0x5857c0 in do_one_cmd /root/github_vim/src/ex_docmd.c:2570
    #17 0x57c853 in do_cmdline /root/github_vim/src/ex_docmd.c:992
    #18 0x89e715 in do_source_ext /root/github_vim/src/scriptfile.c:1674
    #19 0x89f8aa in do_source /root/github_vim/src/scriptfile.c:1801
    #20 0x89c32d in cmd_source /root/github_vim/src/scriptfile.c:1174
    #21 0x89c3a0 in ex_source /root/github_vim/src/scriptfile.c:1200
    #22 0x5857c0 in do_one_cmd /root/github_vim/src/ex_docmd.c:2570
    #23 0x57c853 in do_cmdline /root/github_vim/src/ex_docmd.c:992
    #24 0x57ab0e in do_cmdline_cmd /root/github_vim/src/ex_docmd.c:586
    #25 0xb6de7a in exe_commands /root/github_vim/src/main.c:3133
    #26 0xb66d6a in vim_main2 /root/github_vim/src/main.c:780
    #27 0xb66570 in main /root/github_vim/src/main.c:432
    #28 0x7fa2ab18220f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #29 0x7fa2ab1822bb in __libc_start_main_impl ../csu/libc-start.c:409
    #30 0x404f24 in _start (/root/github_vim/src/vim+0x404f24)

0x619000000981 is located 0 bytes to the right of 1025-byte region [0x619000000580,0x619000000981)
allocated by thread T0 here:
    #0 0x7fa2ab5141c7 in __interceptor_malloc (/usr/lib64/libasan.so.6+0xaf1c7)
    #1 0x405370 in lalloc /root/github_vim/src/alloc.c:246
    #2 0x405161 in alloc /root/github_vim/src/alloc.c:151
    #3 0xb66fc1 in common_init /root/github_vim/src/main.c:914
    #4 0xb66220 in main /root/github_vim/src/main.c:185
    #5 0x7fa2ab18220f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

SUMMARY: AddressSanitizer: heap-buffer-overflow (/usr/lib64/libasan.so.6+0x52fe3) 
Shadow bytes around the buggy address:
  0x0c327fff80e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c327fff80f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c327fff8100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c327fff8110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c327fff8120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c327fff8130:[01]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c327fff8140: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c327fff8150: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fff8160: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fff8170: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fff8180: fd fd fd fd fd fd fd fd 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
  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
  Shadow gap:              cc




This vulnerability is capable of crashing software, modify memory, and possible remote execution.

We are processing your report and will contact the vim team within 24 hours. 19 days ago
xiaoge1001 modified the report
18 days ago
We have contacted a member of the vim team and are waiting to hear back 18 days ago
We have sent a follow up to the vim team. We will try again in 7 days. 15 days ago
13 days ago


There was no response for a long time, so I decided to try to fix it.

xiaoge1001 submitted a
13 days ago
13 days ago


I have verified that the patch is valid and the problem will not reproduce.

vim/vim maintainer validated this vulnerability 11 days ago

The POC is rather complicated, Ken Takata found a much simpler one.

xiaoge1001 has been awarded the disclosure bounty
The fix bounty is now up for grabs
The researcher's credibility has increased: +7
vim/vim maintainer
11 days ago


I would like to mark this as fixed by patch 9.0.0060, but I can't select myself as fixer. The patch suggested above is not a good fix. @admin

Jamie Slome
11 days ago


Hi Bram, just responded to your e-mail. But in short, you need to ensure that you are not auth'ed as a magic maintainer, but instead are signed in with your GitHub account.

Please clear any tokens from your URL, and sign out / sign in again. Should work 👍

Bram Moolenaar confirmed that a fix has been merged on 5fa9f2 11 days ago
Bram Moolenaar has been awarded the fix bounty
7 days ago


@brammool There is a problem with the associated patch. It should be patch 9.0.0060 not patch 9.0.0061, but the link given above is the link of patch 9.0.0061(https://www.github.com/vim/vim/commit/5fa9f2). The patch given by NVD is also patch 9.0.0061, which should be problematic.

Jamie Slome
6 days ago


@Bram - let me know if you need any support on the above, i.e. adjusting the CVE 👍

Bram Moolenaar
6 days ago


I guess the right commit is b9e717367c395490149495cf375911b5d9de889e

Note that I never use those hex numbers, we use human-readable patch numbers.

Jamie Slome
5 days ago


@bram - would you like me to update the report and CVE?

Bram Moolenaar
5 days ago


Whatever. I only care about fixing problems, I don't care much about the bookkeeping.

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