Medium

decompress: Arbitrary File Write via Archive Extraction (Zip Slip)

  • Disclosed: 05.06.2026
  • Updated: 11.10.2026 10:22

All versions of the package decompress are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip) when extracting a ZIP archive containing two entries with the same path - the first being a symlink to an arbitrary target and the second being a regular file - the file content is written through the symlink to the target location outside the output directory. This is due to the microtask processing order that checks readlink for the second file before resolving symlink for the first file. An attacker can write arbitrary files on the host filesystem potentially leading to remote code execution by providing a specially crafted ZIP archive.

Note:

This bypasses all existing path traversal protections including preventWritingThroughSymlink, added as a part of the fix for CVE-2020-12265.

Affected software

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PlatformPackageVulnerable versionsFixed in
npm package decompress <= 4.2.1 no fix

References

CVSS score 6.4/10
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L
Weakness (CWE)
CWE-22, CWE-29
Platform
npm
Package
decompress
Disclosed
05.06.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-h39j-r5qq-r9mm - CC BY 4.0

Vulnerability history: decompress

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
5
First → latest
09.2020 09.2026
Without a fix
4
Exploited in attacks
0

Severity breakdown

  • Critical 3
  • Medium 2

Disclosures per year

  1. 2020: 1
  2. 2021: 0
  3. 2022: 0
  4. 2023: 0
  5. 2024: 0
  6. 2025: 0
  7. 2026: 4
  1. Critical · 9.1 CVE-2026-101894 <= 4.2.1 no fix
  2. decompress: Arbitrary File Write via Archive Extraction (Zip Slip) this entry
    Medium · 6.4 CVE-2026-10732 <= 4.2.1 no fix
  3. Critical · 9.8 CVE-2020-12265 < 4.2.1 4.2.1

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