{"id":"CVE-2026-117556","revision":"46dd6898c1c84abeaffe11213c586f15","records":[{"revision":"46dd6898c1c84abeaffe11213c586f15","observedAt":"2026-10-28T17:46:48.824+00:00","statement":{"source":"cve-program","id":"CVE-2026-117556","aliases":[],"title":"zchunk before 1.5.5 Heap Out-of-Bounds Read via read_preface()","description":"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.","state":0,"publishedAt":"2026-10-27T13:07:51.708+00:00","modifiedAt":"2026-10-28T16:17:15.487+00:00","affected":[{"ecosystem":"Vendor product","name":"zchunk","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"zchunk\",\n                    \"product\": \"zchunk\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"0\",\n                            \"lessThan\": \"1.5.5\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"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","score":5.3,"severity":"MEDIUM"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L","score":4.3,"severity":"MEDIUM"}],"references":["https://github.com/zchunk/zchunk/issues/119","https://github.com/zchunk/zchunk","https://github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1df","https://github.com/zchunk/zchunk/releases/tag/1.5.5","https://github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167","https://www.vulncheck.com/advisories/zchunk-before-1.5.5-heap-out-of-bounds-read-via-read-preface"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-117556","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-117556","identifiers":["CVE-2026-117556"]},"retained":false,"historicalAffected":[]}],"coverage":[]}