{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-117556", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-10-27T11:25:20.941Z", "datePublished": "2026-10-27T13:07:51.708Z", "dateUpdated": "2026-10-27T13:07:51.708Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-10-27T13:07:51.708Z"}, "datePublic": "2026-10-22T00:00:00.000Z", "title": "zchunk before 1.5.5 Heap Out-of-Bounds Read via read_preface()", "descriptions": [{"lang": "en", "value": "zchunk before 1.5.5 contains a heap out-of-bounds read vulnerability in read_preface() in src/lib/header.c that passes the total header length instead of remaining bytes to compint parsing functions. Attackers can supply a crafted .zck file whose header ends inside a compressed integer, causing reads past the heap header buffer and crashing the application."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Out-of-bounds Read", "cweId": "CWE-125", "type": "CWE"}]}], "affected": [{"vendor": "zchunk", "product": "zchunk", "defaultStatus": "unaffected", "versions": [{"status": "affected", "version": "0", "lessThan": "1.5.5", "versionType": "semver"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:zchunk:zchunk:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.5.5"}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 5.3, "baseSeverity": "MEDIUM"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM"}}], "references": [{"url": "https://github.com/zchunk/zchunk/issues/119", "tags": ["issue-tracking"], "name": "GitHub Issue #119"}, {"url": "https://github.com/zchunk/zchunk", "tags": ["product"]}, {"url": "https://github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1df", "tags": ["patch"]}, {"url": "https://github.com/zchunk/zchunk/releases/tag/1.5.5", "tags": ["release-notes"], "name": "zchunk 1.5.5 Release Notes"}, {"url": "https://github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167", "tags": ["technical-description"]}, {"name": "VulnCheck Advisory: zchunk before 1.5.5 Heap Out-of-Bounds Read via read_preface()", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/zchunk-before-1.5.5-heap-out-of-bounds-read-via-read-preface"}], "credits": [{"lang": "en", "value": "HaiND from the Post and Telecommunication Institute of Technology", "type": "finder"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

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