CVE-2026-117556

EUVD-2026-110834
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
4.3 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
zchunkzchunk
𝑥
< 1.5.5
CNA
Common Weakness Enumeration
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
https://www.vulncheck.com/advisories/zchunk-before-1.5.5-heap-out-of-bounds-read-via-read-preface