Vulnerability in Moritz Bunkus Mkvtoolnix
CVE-2026-90783
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (10.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- codeberg.org/mbunkus/mkvtoolnix/commit/1495126138e086080f0163bee27fafbdf956a1d0 (patch)
- codeberg.org/mbunkus/mkvtoolnix/src/tag/release-101.0/lib/avilib-0.6.10/avilib.c (technical-description)
- codeberg.org/mbunkus/mkvtoolnix (product)
- www.vulncheck.com/advisories/mkvtoolnix-through-101.0-heap-buffer-overflow-via-… (third-party-advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2026-90783?
- CVE-2026-90783 is a high-severity vulnerability in Moritz Bunkus Mkvtoolnix, classified under Integer Overflow to Buffer Overflow. CVSS score: 7.8/10. Published 2026-09-13.
- How severe is CVE-2026-90783?
- High severity. CVSS v3 base score is 7.8 out of 10.