# CVE-2026-90783: mkvtoolnix: MKVToolNix through 101.0 contains a heap buffer overflow in the bundled avilib library's ODML superindex parser due t...

CVE-2026-90783 is fixed in 5 products on 1 platform, first by OPENSUSE-SU-2026:21867-1, released September 16, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-90783
- Priority: High
- CVSS: n/a (important)
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 13, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | mkvtoolnix Debian 12.15 (bookworm) | 74.0.0-1+deb12u1 | [DEBIAN-CVE-2026-90783](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90783.md) | Sep 17, 2026 |
| Linux | mkvtoolnix Debian 13.5 (trixie) | 92.0-1+deb13u1 | [DEBIAN-CVE-2026-90783](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90783.md) | Sep 17, 2026 |
| Linux | mkvtoolnix Debian 14 | 101.0-2 | [DEBIAN-CVE-2026-90783](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90783.md) | Sep 17, 2026 |
| Linux | mkvtoolnix Fedora 43 | 96.0-2.fc43 | [FEDORA-2026-8918B368F4](https://patchblox.com/security/data/fix/linux/fedora-2026-8918b368f4.md) | Nov 7, 2026 |
| Linux | mkvtoolnix opensuse-leap 16.0 | 95.0-bp160.2.1 | [OPENSUSE-SU-2026:21867-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21867-1.md) | Sep 16, 2026 |
| Linux | mkvtoolnix-debuginfo Fedora 43 | 96.0-2.fc43 | [FEDORA-2026-8918B368F4](https://patchblox.com/security/data/fix/linux/fedora-2026-8918b368f4.md) | Nov 7, 2026 |
| Linux | mkvtoolnix-debugsource Fedora 43 | 96.0-2.fc43 | [FEDORA-2026-8918B368F4](https://patchblox.com/security/data/fix/linux/fedora-2026-8918b368f4.md) | Nov 7, 2026 |
| Linux | mkvtoolnix-gui Fedora 43 | 96.0-2.fc43 | [FEDORA-2026-8918B368F4](https://patchblox.com/security/data/fix/linux/fedora-2026-8918b368f4.md) | Nov 7, 2026 |
| Linux | mkvtoolnix-gui-debuginfo Fedora 43 | 96.0-2.fc43 | [FEDORA-2026-8918B368F4](https://patchblox.com/security/data/fix/linux/fedora-2026-8918b368f4.md) | Nov 7, 2026 |

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Data as of 2026-11-10T07:50:38Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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