CVE-2026-63436: medium-severity vulnerability in zeroturnaround zt-zip
zt-zip: Path traversal in fluent API unpack
Published
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.1epss 0.2%
zt-zip is a Java library that provides convenience methods for ZIP archive manipulation. Prior to 1.18.0, the Zips.get(zip).unpack().destination(outputDir).process() fluent API in src/main/java/org/zeroturnaround/zip/Zips.java constructs output files directly from ZIP entry names without applying the destination-boundary validation used by ZipUtil.unpack(...). A crafted entry containing parent-directory traversal can therefore write outside outputDir through both the normal copy branch and the ZipEntryTransformer branch. Applications that extract untrusted archives only through ZipUtil.unpack(...) are unaffected because that API already calls checkDestinationFileForTraversal. This issue is fixed in version 1.18.0.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
Affected products
zeroturnaround · zt-zipRelated CVEs — zeroturnaround zt-zip
In the same product, most dangerous first.