CVE-2026-86071

Low CVSS 3.7

Published 2026-09-16 · last changed 2026-09-17

The fix

We hold no Microsoft remediation data for CVE-2026-86071, 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

Junrar is an open source Java RAR archive library. Prior to version 7.6.1, LocalFolderExtractor in src/main/java/com/github/junrar/LocalFolderExtractor.java can create directories outside the intended extraction root when processing a crafted archive entry. LocalFolderExtractor.createFile() validates only the final canonical file path, while LocalFolderExtractor.makeFile() creates intermediate path segments with unchecked mkdir() calls. An entry can therefore make the final path resolve inside the destination while causing intermediate directory creation outside it, enabling filesystem pollution or file-versus-directory squatting that can make later security-sensitive writes fail. The demonstrated impact is directory creation, not unconditional arbitrary file-content write. This issue is fixed in version 7.6.1.

Sources

NVD record for CVE-2026-86071

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N