{"cve":"CVE-2026-117556","nvd":{"published":"2026-10-27T14:16:36.340","modified":"2026-10-27T16:04:22.707","status":"Deferred","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.","cvss_v4":{"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},"cvss_v3":{"version":"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},"cwes":["CWE-125"],"references":["https://github.com/zchunk/zchunk","https://github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167","https://github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1df","https://github.com/zchunk/zchunk/issues/119","https://github.com/zchunk/zchunk/releases/tag/1.5.5"],"products":[],"source":"nvd","synced_at":"2026-10-27T16:16:04.830248275+00:00"},"epss":null,"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}