{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-90783", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-09-13T12:01:36.028Z", "datePublished": "2026-09-13T12:22:02.443Z", "dateUpdated": "2026-09-13T12:22:02.443Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-09-13T12:22:02.443Z"}, "datePublic": "2026-08-25T00:00:00.000Z", "title": "MKVToolNix through 101.0 Heap Buffer Overflow via avilib ODML Superindex Integer Wraparound", "descriptions": [{"lang": "en", "value": "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Integer Overflow to Buffer Overflow", "cweId": "CWE-680", "type": "CWE"}]}], "affected": [{"defaultStatus": "unaffected", "vendor": "Moritz Bunkus", "product": "MKVToolNix", "repo": "https://codeberg.org/mbunkus/mkvtoolnix", "versions": [{"version": "0", "lessThanOrEqual": "101.0", "status": "affected", "versionType": "custom"}, {"version": "1495126138e086080f0163bee27fafbdf956a1d0", "status": "unaffected", "versionType": "git"}]}], "metrics": [{"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH"}}, {"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 8.5, "baseSeverity": "HIGH"}}], "references": [{"url": "https://codeberg.org/mbunkus/mkvtoolnix/commit/1495126138e086080f0163bee27fafbdf956a1d0", "tags": ["patch"], "name": "Patch Commit"}, {"url": "https://codeberg.org/mbunkus/mkvtoolnix/src/tag/release-101.0/lib/avilib-0.6.10/avilib.c#L2552-L2570", "tags": ["technical-description"], "name": "Unchecked video superindex allocation in avi_parse_input_file() at release-101.0"}, {"url": "https://codeberg.org/mbunkus/mkvtoolnix", "tags": ["product"]}, {"name": "VulnCheck Advisory: MKVToolNix through 101.0 Heap Buffer Overflow via avilib ODML Superindex Integer Wraparound", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/mkvtoolnix-through-101.0-heap-buffer-overflow-via-avilib-odml-superindex-integer-wraparound"}], "credits": [{"lang": "en", "value": "Tristan Madani", "type": "finder"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "MKVToolNix", "repo": "https://codeberg.org/mbunkus/mkvtoolnix", "vendor": "Moritz Bunkus", "versions": [{"lessThanOrEqual": "101.0", "status": "affected", "version": "0", "versionType": "custom"}, {"status": "unaffected", "version": "1495126138e086080f0163bee27fafbdf956a1d0", "versionType": "git"}]}], "source": "disclosure@vulncheck.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-90783", "lastModified": "2026-09-13T13:16:29.560", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "disclosure@vulncheck.com", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.5, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}]}, "published": "2026-09-13T13:16:29.560", "references": [{"source": "disclosure@vulncheck.com", "url": "https://codeberg.org/mbunkus/mkvtoolnix"}, {"source": "disclosure@vulncheck.com", "url": "https://codeberg.org/mbunkus/mkvtoolnix/commit/1495126138e086080f0163bee27fafbdf956a1d0"}, {"source": "disclosure@vulncheck.com", "url": "https://codeberg.org/mbunkus/mkvtoolnix/src/tag/release-101.0/lib/avilib-0.6.10/avilib.c#L2552-L2570"}, {"source": "disclosure@vulncheck.com", "url": "https://www.vulncheck.com/advisories/mkvtoolnix-through-101.0-heap-buffer-overflow-via-avilib-odml-superindex-integer-wraparound"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-680"}], "source": "disclosure@vulncheck.com", "type": "Primary"}]}

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