# CVE-2026-63436: zt-zip: Path traversal in fluent API unpack

Status: published. Published: 2026-11-03. Updated: 2026-11-09.

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.

## Remediation

- fix: org.zeroturnaround:zt-zip (maven): GitHub reports patched versions 1.18.0. Check the advisory for the affected release branch. (source: GitHub GHSA-52c6-99qm-3hqr) — https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-52c6-99qm-3hqr

## Affected products and versions

- zeroturnaround / zt-zip: < 1.18.0 (affected). Source: CNA: GitHub_M
-  / org.zeroturnaround:zt-zip (org.zeroturnaround:zt-zip): <= 1.17 (affected, GitHub advisory range). Source: GitHub GHSA-52c6-99qm-3hqr

## Severity and prioritization

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L; source: CNA: GitHub_M

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.24% as of 2026-11-09; percentile 15.37%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-22

## Exploit evidence

- exploit: https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-52c6-99qm-3hqr (ADP: CISA-ADP)

## References

- https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-52c6-99qm-3hqr (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/zeroturnaround/zt-zip/pull/180 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/zeroturnaround/zt-zip/commit/59a76ad576b0fcd50ea018e3608afb946c1492fd (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/zeroturnaround/zt-zip/releases/tag/v1.18.0 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-52c6-99qm-3hqr (ADP: CISA-ADP; exploit)

- https://github.com/zeroturnaround/zt-zip/commit/59a76ad576b0fcd50ea018e3608afb946c1492fd (security-advisories@github.com)

- https://github.com/zeroturnaround/zt-zip/pull/180 (security-advisories@github.com)

- https://github.com/zeroturnaround/zt-zip/releases/tag/v1.18.0 (security-advisories@github.com)

- https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-52c6-99qm-3hqr (security-advisories@github.com)

- https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-52c6-99qm-3hqr (GitHub Security Advisories; advisory)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-63436; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63436; retrieved 2026-11-04; source updated 2026-11-03

- GitHub Security Advisories: https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-52c6-99qm-3hqr; retrieved 2026-11-04; source updated 2026-07-16

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-63436; retrieved 2026-11-09; source updated Not reported

Revision: 525b96f49f334320d8099faa839c2ae18fa7ccd6f4703037307f62cc1e0a82c0

Canonical: https://y2.dev/cve/CVE-2026-63436

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