CVE-2026-117556
zchunk before 1.5.5 Heap Out-of-Bounds Read via read_preface()
zchunk zchunk
CVSS
5.3MediumExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)No scoreNo FIRST EPSS score in this snapshot yet
What fixes it
- 1.5.5zchunkCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
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.
Text from CVE List
Affected versions 1
- zchunkaffected: all versions before 1.5.5CVE List
References 6
- github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1dfFixvia CVE List
- github.com/zchunk/zchunk/releases/tag/1.5.5Fixvia CVE List
- vulncheck.com/advisories/zchunk-before-1.5.5-heap-out-of-bounds-read-via-read-prefaceAdvisoryvia CVE List
- github.com/zchunk/zchunk/issues/119Referencevia CVE List
- github.com/zchunk/zchunkReferencevia CVE List
- github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167Referencevia CVE List