CVE-2026-63499
UnratedPublished 2026-11-03 ยท last changed 2026-11-03
The fix
We hold no Microsoft remediation data for CVE-2026-63499, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.
What it is
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.