{"id":"UBUNTU-CVE-2026-117556","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.","modified":"2026-10-28T20:17:46.303811101Z","published":"2026-10-27T14:16:00Z","upstream":["CVE-2026-117556"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-117556"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-117556"},{"type":"REPORT","url":"https://github.com/zchunk/zchunk"},{"type":"REPORT","url":"https://github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167"},{"type":"REPORT","url":"https://github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1df"},{"type":"REPORT","url":"https://github.com/zchunk/zchunk/issues/119"},{"type":"REPORT","url":"https://github.com/zchunk/zchunk/releases/tag/1.5.5"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/zchunk-before-1.5.5-heap-out-of-bounds-read-via-read-preface"}],"affected":[{"package":{"name":"zchunk","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/zchunk?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.9+ds1-1","1.1.16+ds1-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.1.16+ds1-1","binary_name":"libzck1"},{"binary_version":"1.1.16+ds1-1","binary_name":"zchunk"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-117556.json"}},{"package":{"name":"zchunk","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/zchunk?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.1+ds1-1","1.3.2+ds1-1","1.3.2+ds1-1build1","1.3.2+ds1-1build2"],"ecosystem_specific":{"binaries":[{"binary_name":"libzck1","binary_version":"1.3.2+ds1-1build2"},{"binary_name":"zchunk","binary_version":"1.3.2+ds1-1build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-117556.json"}},{"package":{"name":"zchunk","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/zchunk?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.2+ds1-2","1.5.3+ds1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libzck1","binary_version":"1.5.3+ds1-1"},{"binary_name":"zchunk","binary_version":"1.5.3+ds1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-117556.json"}},{"package":{"name":"zchunk","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/zchunk?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.1+ds1-1","1.5.2+ds1-1","1.5.2+ds1-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libzck1","binary_version":"1.5.2+ds1-2"},{"binary_version":"1.5.2+ds1-2","binary_name":"zchunk"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-117556.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L"},{"type":"CVSS_V4","score":"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"},{"type":"Ubuntu","score":"medium"}]}