CVE-2026-90783

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-13. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.8
EG Score
7.8(high)
EG Risk
35(Track)
EG Risk 35/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

September 13, 2026

Last Modified

September 14, 2026

Advisory Details (4)

Auto-updated Sep 13, 2026
No patch confirmed yet.
generic

MKVToolNix through 101.0 Heap Buffer Overflow via avilib ODML Superindex Integer Wraparound | Advisories | VulnCheck

https://www.vulncheck.com/advisories/mkvtoolnix-through-101.0-heap-buffer-overflow-via-avilib-odml-superindex-integer-wraparound
generic

mbunkus/mkvtoolnix: Creating and working with Matroska files - Codeberg.org

https://codeberg.org/mbunkus/mkvtoolnix
generic

Cookie monster!

https://codeberg.org/mbunkus/mkvtoolnix/src/tag/release-101.0/lib/avilib-0.6.10/avilib.c#L2552-L2570
generic

Cookie monster!

https://codeberg.org/mbunkus/mkvtoolnix/commit/1495126138e086080f0163bee27fafbdf956a1d0

Vendor Advisories for CVE-2026-90783(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 26× in last 7d / 26× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-19 04:38 UTCGHSA enrichment
  2. 2026-09-18 15:28 UTCGHSA enrichment
  3. 2026-09-18 02:14 UTCEG score recompute
  4. 2026-09-18 02:14 UTCGHSA enrichment
  5. 2026-09-17 19:32 UTCEPSS rescore
  6. 2026-09-17 13:05 UTCGHSA enrichment
  7. 2026-09-16 23:56 UTCEG score recompute
  8. 2026-09-16 23:56 UTCGHSA enrichment
  9. 2026-09-16 14:09 UTCEPSS rescore
  10. 2026-09-16 10:47 UTCEG score recompute
  11. 2026-09-16 10:47 UTCGHSA enrichment
  12. 2026-09-16 05:15 UTCEPSS rescore
  13. 2026-09-15 21:38 UTCGHSA enrichment
  14. 2026-09-15 08:29 UTCEG score recompute
  15. 2026-09-15 08:29 UTCGHSA enrichment
  16. 2026-09-15 03:12 UTCEPSS rescore
  17. 2026-09-14 19:20 UTCEG score recompute
  18. 2026-09-14 19:20 UTCGHSA enrichment
  19. 2026-09-14 18:27 UTCEG score recompute
  20. 2026-09-14 18:27 UTCGHSA enrichment
  21. 2026-09-14 15:38 UTCGHSA enrichment
  22. 2026-09-14 02:29 UTCEG score recompute
  23. 2026-09-14 02:29 UTCGHSA enrichment
  24. 2026-09-13 13:20 UTCEG score recompute
  25. 2026-09-13 12:36 UTCEG score recompute
Show 1 more
  1. 2026-09-13 12:34 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-90783?
CVE-2026-90783 is a high vulnerability published on September 13, 2026. 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…
When was CVE-2026-90783 disclosed?
CVE-2026-90783 was first published in the National Vulnerability Database on September 13, 2026, with the most recent update on September 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-90783 actively exploited?
CVE-2026-90783 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.2% of all scored CVEs.
What is the CVSS score of CVE-2026-90783?
CVE-2026-90783 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-90783?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-90783, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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