Heap overflow via ODML superindex integer wraparound
Published Sep 13, 2026 · Updated Sep 13, 2026
Heap buffer overflow in MKVToolNix 101.0 and earlier allows context-dependent attackers to corrupt memory via a crafted AVI file. The bundled avilib ODML superindex parser performs 32-bit allocation arithmetic on an oversized entry count, wraps the result, allocates an undersized heap buffer, and writes entries beyond it. Exploitation requires local users or automated workflows to make mkvmerge parse the file; memory corruption is established, but code execution is not publicly established.
Summary
What happened
Heap buffer overflow in MKVToolNix 101.0 and earlier allows context-dependent attackers to corrupt memory via a crafted AVI file. The bundled avilib ODML superindex parser performs 32-bit allocation arithmetic on an oversized entry count, wraps the result, allocates an undersized heap buffer, and writes entries beyond it. Exploitation requires local users or automated workflows to make mkvmerge parse the file; memory corruption is established, but code execution is not publicly established.
The record
- CVE
- CVE-2026-90783
- Published
- Sep 13, 2026
- Updated
- Sep 13, 2026
- Vendor
- Moritz Bunkus
- Product
- MKVToolNix
- Classifications
- Unavailable
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 13, 2026CVE publishedPublication date reported by the CVE source.
- Sep 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=101.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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Your stack
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