MKVToolNix vulnerability

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 13 Sep 2026Updated 13 Sep 20264 sources
CVSS 8.5

What happened

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 versions

MKVToolNix: 0 through 101.0 (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.