---
title: "CVE-2018-20834\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2018-20834?format=md
keywords: index, follow
---

# CVE-2018-20834

Publication date 30 April 2019

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2018-20834?format=md#impact-score)

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## Description

A vulnerability was found in node-tar before version 4.4.2 (excluding
version 2.2.2). 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. A patch has
been applied to node-tar v2.2.2).

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| node-tar | 19.04 disco | Not affected |
| 18.10 cosmic | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not affected |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | High |
  | Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-20834)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-20834)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-20834)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-20834)

### Other references

* <https://github.com/npm/node-tar/commit/b0c58433c22f5e7fe8b1c76373f27e3f81dcd4c8>
* <https://hackerone.com/reports/344595>
* <https://github.com/npm/node-tar/compare/58a8d43...a5f7779>
* <https://www.cve.org/CVERecord?id=CVE-2018-20834>