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VulnerabilityPublished

CVE-2026-63499: zeroturnaround zt-zip · Relative Path Traversal

Affects zeroturnaround zt-zipSource CVE Database V5

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Not known to be exploited · CVSS 6.9 Medium : upgrade to 1.18.1 when convenient.

Data as of 3 Nov 2026, 19:58 UTC

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 4.06.9
Patch
Available – fixed in 1.18.1
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.

What to do

Upgrade zt-zip and com.zeroturnaround/zt-zip to 1.18.1.

Affected software

ProductAffectedFixed in
zeroturnaroundzt-zipAffected
  • <1.18.1
Fixed in
  • 1.18.1
Mavencom.zeroturnaround/zt-zippkg:maven/com.zeroturnaround/zt-zipOther threatsAffected
  • <1.18.1
Fixed in
  • 1.18.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to zt-zip version 1.18.1 or later, where this vulnerability is fixed. Applications unpacking untrusted ZIP files should ensure they use the patched version to prevent permission manipulation via crafted ZIP entries.

Description

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.

References

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