{"schema":"threatline.record/2","record":{"id":"CVE-2026-117556","aliases":[],"summary":"zchunk before 1.5.5 Heap Out-of-Bounds Read via read_preface()","details":"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.","categories":["Unclassified"],"product":"zchunk","vendor":"zchunk","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-117556","source_modified_at":"2026-10-27T13:07:51.708Z","fetched_at":"2026-10-27T16:27:21.584480Z","product":"zchunk","vendor":"zchunk","versions":[{"status":"affected","version":"0","lessThan":"1.5.5","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-117556","source_modified_at":"2026-10-27T13:07:51.708Z","fetched_at":"2026-10-27T16:27:21.584480Z","package":{"name":"zchunk","ecosystem":null},"version":"1.5.5","basis":"first unaffected version stated in the CVE record"}],"cvss":5.3,"severity":"Medium","kev":{"listed":false},"epss":{"probability":null,"percentile":null,"score_date":null},"published_at":"2026-10-27T13:07:51.708Z","modified_at":"2026-10-27T13:07:51.708Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-117556","fetched_at":"2026-10-27T16:27:21.584480Z","source_modified_at":"2026-10-27T13:07:51.708Z"}],"sources":["CVE List"],"references":[{"source":"CVE List","url":"https://github.com/zchunk/zchunk/issues/119","tags":["issue-tracking"]},{"source":"CVE List","url":"https://github.com/zchunk/zchunk","tags":["product"]},{"source":"CVE List","url":"https://github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1df","tags":["patch"]},{"source":"CVE List","url":"https://github.com/zchunk/zchunk/releases/tag/1.5.5","tags":["release-notes"]},{"source":"CVE List","url":"https://github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167","tags":["technical-description"]},{"source":"CVE List","url":"https://www.vulncheck.com/advisories/zchunk-before-1.5.5-heap-out-of-bounds-read-via-read-preface","tags":["third-party-advisory"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-27T13:07:51.708Z","content_hash":"026df9aa3a037b394ee07c358c6d20aa5dde6a7e62068dab77943b00b45301b2"}}