CVSS 3.1
6.1 mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:LCVE-2026-63436
Medium (6.1). EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
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.
Severity
- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 15th percentile. Scored 2026-11-04. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory (Path traversal)
- OWASP Top 10
- A01:2025 Broken Access Control
- Published
- Record from
- the NVD, synced
Ask an AI about this CVE
Show the prompt
Explain CVE-2026-63436 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-63436?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-63436?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-63436 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| zeroturnaround zt-zip | < 1.18.0 |
Attack patterns (CAPEC)
- CAPEC-64 Using Slashes and URL Encoding Combined to Bypass Validation Logic Likelihood: High · Severity: High
- CAPEC-76 Manipulating Web Input to File System Calls Likelihood: High · Severity: Very High
- CAPEC-78 Using Escaped Slashes in Alternate Encoding Likelihood: High · Severity: High
- CAPEC-79 Using Slashes in Alternate Encoding Likelihood: High · Severity: High
- CAPEC-126 Path Traversal Likelihood: High · Severity: Very High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.