CVE-2021-32804

Workarounds

Users may work around this vulnerability without upgrading by creating a custom onentry method which sanitizes the entry.path or a filter method which removes entries with absolute paths.

const path = require('path')
const tar = require('tar')

tar.x({
  file: 'archive.tgz',
  // either add this function...
  onentry: (entry) => {
    if (path.isAbsolute(entry.path)) {
      entry.path = sanitizeAbsolutePathSomehow(entry.path)
      entry.absolute = path.resolve(entry.path)
    }
  },

  // or this one
  filter: (file, entry) => {
    if (path.isAbsolute(entry.path)) {
      return false
    } else {
      return true
    }
  }
})

Users are encouraged to upgrade to the latest patch versions, rather than attempt to sanitize tar input themselves.

Arbitrary File Creation, Arbitrary File Overwrite, Arbitrary Code Execution

node-tar aims to prevent extraction of absolute file paths by turning absolute paths into relative paths when the preservePaths flag is not set to true. This is achieved by stripping the absolute path root from any absolute file paths contained in a tar file. For example /home/user/.bashrc would turn into home/user/.bashrc.

This logic was insufficient when file paths contained repeated path roots such as ////home/user/.bashrc. node-tar would only strip a single path root from such paths. When given an absolute file path with repeating path roots, the resulting path (e.g. ///home/user/.bashrc) would still resolve to an absolute path, thus allowing arbitrary file creation and overwrite.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2021-32804 has a CVSS score of 8.2 (High). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.2.2, 4.4.14, 5.0.6, 6.1.1); upgrading removes the vulnerable code path.

Kodem intelligence

3.2.2 || 4.4.14 || 5.0.6 || 6.1.1

NOTE: an adjacent issue CVE-2021-32803 affects this release level. Please ensure you update to the latest patch levels that address CVE-2021-32803 as well if this adjacent issue affects your node-tar use case.

1. What is CVE-2021-32804? CVE-2021-32804 is a high-severity path traversal vulnerability in tar (npm), affecting versions < 3.2.2. It is fixed in 3.2.2, 4.4.14, 5.0.6, 6.1.1. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2021-32804? CVE-2021-32804 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of tar are affected by CVE-2021-32804? tar (npm) versions < 3.2.2 is affected.
4. Is there a fix for CVE-2021-32804? Yes. CVE-2021-32804 is fixed in 3.2.2, 4.4.14, 5.0.6, 6.1.1. Upgrade to this version or later.
5. Is CVE-2021-32804 exploitable, and should I be worried? Whether CVE-2021-32804 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2021-32804 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2021-32804?
   • Upgrade tar to 3.2.2 or later
   • Upgrade tar to 4.4.14 or later
   • Upgrade tar to 5.0.6 or later
   • Upgrade tar to 6.1.1 or later