---
id: CVE-2026-85396
title: >-
  rubyzip versions before 3.4.0 contain a path traversal vulnerability in
  Zip::Entry#extract that fails to properly validate extraction paths using
  prefix comparison without trailing separators
summary: >-
  rubyzip versions before 3.4.0 contain a path traversal vulnerability in
  Zip::Entry#extract that fails to properly validate extraction paths using
  prefix comparison without trailing separators. Attackers can craft archive
  entries with nam…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-22
published: '2026-09-03'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:28:01.780'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85396'
references:
  - url: 'https://github.com/geo-chen/oss/blob/main/rubyzip.md'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/rubyzip/rubyzip'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/rubyzip/rubyzip/blob/v3.3.1/lib/zip/entry.rb'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/rubyzip/rubyzip/commit/17edfbf4423b83211b075acc23a7d8640da63449
    label: disclosure@vulncheck.com
  - url: 'https://github.com/rubyzip/rubyzip/releases/tag/v3.4.0'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/rubyzip-before-3.4.0-path-traversal-in-zip-entry-extract-via-sibling-directory-prefix
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00564
epssPercentile: 0.4449
ingestedAt: '2026-09-24T20:51:40.241Z'
---

## Overview

rubyzip versions before 3.4.0 contain a path traversal vulnerability in Zip::Entry#extract that fails to properly validate extraction paths using prefix comparison without trailing separators. Attackers can craft archive entries with names like ../upload_backup/owned.sh to write files outside the intended extraction directory into sibling paths sharing the destination prefix.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.