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TI-2026-84460 Aliases CVE-2026-63499

ZipUtil.unpack in zt-zip can change output directory permissions

Priority MEDIUM 64CWE-23Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · High · Low
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

zt-zip before 1.18.1 is affected. ZipUtil.unpack applies stored ZIP entry permissions to the output directory when an entry name such as / or ./ resolves to that directory itself (CWE-23). An attacker who supplies a crafted ZIP file that a user unpacks can replace restrictive output directory permissions with attacker-chosen ones.

Written with Claude Haiku 5.5 from the sources below · 2026-11-03

Description from the CNA

zt-zip is a Java library that provides convenience methods for ZIP archive manipulation. Prior to 1.18.1, ZipUtil.unpack(...) can apply stored ZIP-entry permissions to the extraction output directory when an entry name such as / or ./ resolves to that directory itself. Because the path traversal checks permit self-referencing entries that do not escape the destination, the unpacker's permission-handling path can replace restrictive output-directory permissions with attacker-supplied permissions. This affects applications that unpack untrusted ZIP files, and POSIX systems demonstrate the issue directly, while ZTFilePermissionsUtil.fetchDefaultStrategy provides fallback permission handling on other supported systems. This issue is fixed in version 1.18.1.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0028 20th percentileScored 2026-11-07
Fix Fixed zt-zip (zeroturnaround): 1.18.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
zeroturnaroundzt-zipbefore 1.18.11.18.1Patch availableCNA
  • zt-zip Vendorzeroturnaround Affected before 1.18.1 Fixed in 1.18.1 Patch available CNA

Remediation

Upgrade zt-zip to version 1.18.1, which fixes this issue.

Written with Claude Haiku 5.5 from the sources below · 2026-11-03

  • Fix · CNA zt-zip (zeroturnaround) Fixed in 1.18.1

Timeline

  1. 2026-11-03 Threatist record created from CVE-2026-63499
  2. 2026-11-03 CISA SSVC decision points changed

References

Other 4

  • TI-2026-84459 Path traversal in zt-zip fluent API unpack lets crafted archives write files CVSS 3.1MEDIUM 6.1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences