CVE-2026-63436

MEDIUM 6.1

zt-zip: Path traversal in fluent API unpack

CVSS Score

6.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-22
Vendor	zeroturnaround
Product	zt-zip
Published	Nov 3, 2026

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CVSS v3 Breakdown

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

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

Low

Affected Versions

zeroturnaround / zt-zip

< 1.18.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-52c6-99qm-3hqr github.com: https://github.com/zeroturnaround/zt-zip/pull/180 github.com: https://github.com/zeroturnaround/zt-zip/commit/59a76ad576b0fcd50ea018e3608afb946c1492fd github.com: https://github.com/zeroturnaround/zt-zip/releases/tag/v1.18.0