{"id":"CVE-2026-117556","published":"2026-10-27T14:16:36.340","lastModified":"2026-10-27T16:04:22.707","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.","cvssScore":4.3,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L","cwes":["CWE-125"],"vendors":[],"products":[],"references":[{"url":"https://github.com/zchunk/zchunk","tags":[]},{"url":"https://github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167","tags":[]},{"url":"https://github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1df","tags":[]},{"url":"https://github.com/zchunk/zchunk/issues/119","tags":[]},{"url":"https://github.com/zchunk/zchunk/releases/tag/1.5.5","tags":[]},{"url":"https://www.vulncheck.com/advisories/zchunk-before-1.5.5-heap-out-of-bounds-read-via-read-preface","tags":[]}],"exploitRefs":[{"url":"https://github.com/zchunk/zchunk","tags":[]},{"url":"https://github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167","tags":[]},{"url":"https://github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1df","tags":[]},{"url":"https://github.com/zchunk/zchunk/issues/119","tags":[]},{"url":"https://github.com/zchunk/zchunk/releases/tag/1.5.5","tags":[]}],"hasPoc":true,"ai":null}