Junrar has an arbitrary file write due to backslash Path Traversal bypass in LocalFolderExtractor on Linux/Unix

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS

• CVE-2026-28208: 14.74% estimated exploitation activity in the next 30 days; percentile 96.68 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A backslash path traversal vulnerability in LocalFolderExtractor allows an attacker to write arbitrary files with attacker-controlled content anywhere on the filesystem when a crafted RAR archive is extracted on Linux/Unix. This can often lead to remote code execution (e.g., overwriting shell profiles, source code, cron jobs, etc). Details The createFile() method in LocalFolderExtractor.java validates extraction paths using getCanonicalPath().startsWith() to ensure files stay within the destination directory: On Linux/Unix, backslashes are literal filename characters, not path separators. A RAR entry named ..\..\tmp\evil.txt is treated by getCanonicalPath() as a single literal filename containing backslash characters — no .. resolution occurs, and the startsWith check passes. However, makeFile() then splits the filename on backslashes and reconstructs the path using the platform's file separator: This converts the literal backslashes into real directory traversal:…

Published by the source

27 Feb 2026, 22:09 UTC

Last modified by the source

27 Feb 2026, 22:09 UTC

Source last checked

26 Oct 2026, 16:44 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-j273-m5qq-6825

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# Patch Next advisory brief: CVE-2026-28208

Advisory: Junrar has an arbitrary file write due to backslash Path Traversal bypass in LocalFolderExtractor on Linux/Unix
IDs: CVE-2026-28208, GHSA-j273-m5qq-6825
Record: https://patchnext.com/advisories/cve-2026-28208 (revision 1, source checked 26 Oct 2026, 16:44 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: com.github.junrar:junrar 7.5.8. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven com.github.junrar:junrar: affected < 7.5.8; fixed in 7.5.8

## Suggested inspection (read-only)
- Maven com.github.junrar:junrar: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on com.github.junrar:junrar.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-j273-m5qq-6825 (GitHub-reviewed advisory GHSA-j273-m5qq-6825 lists affected ranges: Maven com.github.junrar:junrar >=0 <7.5.8)

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