CVE-2026-117556
zchunk before 1.5.5 Heap Out-of-Bounds Read via read_preface()
CVSS Score
4.3
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-125 |
| Vendor | zchunk |
| Product | zchunk |
| Published | Oct 27, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
zchunk / zchunk
0 < 1.5.5
References
github.com: https://github.com/zchunk/zchunk/issues/119 github.com: https://github.com/zchunk/zchunk github.com: https://github.com/zchunk/zchunk/commit/02b371a64bf98245df97315d07c684a0ca5ea1df github.com: https://github.com/zchunk/zchunk/releases/tag/1.5.5 github.com: https://github.com/zchunk/zchunk/blob/1.5.4/src/lib/header.c#L167 vulncheck.com: https://www.vulncheck.com/advisories/zchunk-before-1.5.5-heap-out-of-bounds-read-via-read-preface
Credits
HaiND from the Post and Telecommunication Institute of Technology