Description
MKVToolNix through 101.0 contains a heap buffer overflow in the bundled avilib library's ODML superindex parser due to integer wraparound in 32-bit arithmetic. Attackers can craft a malicious AVI file with oversized entry counts that cause an undersized heap allocation, allowing a heap buffer overflow when the file is parsed with mkvmerge.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Moritz Bunkus | MKVToolNix | ≤ 101.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | mkvtoolnix | 101.0-2 | — |
| Debian 13 | mkvtoolnix | 92.0-1+deb13u1 | — |
| Debian 12 | mkvtoolnix | 74.0.0-1+deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | mkvtoolnix | No fix yet | — |
| Ubuntu 26.04 LTS | mkvtoolnix | No fix yet | — |
| Ubuntu 24.04 LTS | mkvtoolnix | No fix yet | — |
| Ubuntu 22.04 LTS | mkvtoolnix | No fix yet | — |
| Ubuntu 20.04 LTS | mkvtoolnix | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | mkvtoolnix | No fix yet | — |
| Ubuntu 16.04 LTS | mkvtoolnix | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | mkvtoolnix | 101.0-2.1 | openSUSE-SU-2026:11779-1 |
| openSUSE Leap 16.0 | mkvtoolnix | 95.0-bp160.2.1 | openSUSE-SU-2026:21867-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | mkvtoolnix | 99.0-r1 | — |
Advisories 2
- openSUSE-SU-2026:21867-1 Security update for mkvtoolnix SUSE / openSUSE Security Updates · Sep 17, 2026
- openSUSE-SU-2026:11779-1 mkvtoolnix-101.0-2.1 on GA media SUSE / openSUSE Security Updates · Sep 15, 2026
References
- Patch Commit patch
- Unchecked video superindex allocation in avi_parse_input_file() at release-101.0 technical-description
- https://codeberg.org/mbunkus/mkvtoolnix product
- VulnCheck Advisory: MKVToolNix through 101.0 Heap Buffer Overflow via avilib ODML Superindex Integer Wraparound third-party-advisory