CVE-2026-63436

Medium CVSS 6.1

Published 2026-11-03 · last changed 2026-11-03

The fix

We hold no Microsoft remediation data for CVE-2026-63436, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

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.

Sources

NVD record for CVE-2026-63436

CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L