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Fencer Intel
medium 6.9

CVE-2026-63499 json

zt-zip: ZipUtil.unpack can change file permissions of output directory

published 6d ago modified 2h ago also EUVD-2026-116113 , GHSA-v2g6-7r9j-v6px

cvss
6.9
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven org.zeroturnaround:zt-zip 1.18.1

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6d ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/zeroturnaround/zt-zip/security/advisories/GHSA-v2g6-7r9j-v6px referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 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
CNA 4.0 6.9 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
maven org.zeroturnaround:zt-zip
<1.18.1
1.18.1

Affected products

  • zeroturnaround zt-zip

Classification

Weakness
  • CWE-23 Relative Path Traversal

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.