---
title: "CVE-2019-16255\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-2019-16255?format=md
keywords: index, follow
---
# CVE-2019-16255
Publication date 20 November 2019
Last updated 11 July 2025
---
Ubuntu priority
**Medium**
[Why this priority?](https://ubuntu.com/security/cves/about#priority )
## Cvss 3 Severity Score
**8.1 · High**
[Score breakdown](https://ubuntu.com/security/CVE-2019-16255?format=md#impact-score)
Toggle side navigation
## Description
Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 allows
code injection if the first argument (aka the "command" argument) to
Shell#[] or Shell#test in lib/shell.rb is untrusted data. An attacker can
exploit this to call an arbitrary Ruby method.
### From the Ubuntu Security Team
It was discovered that JRuby did not properly sanitize input to Shell#[] and
its alias Shell#test. An attacker could use this vulnerability to execute
arbitrary commands.
## Status
Show unmaintained releases
| Package | Ubuntu Release | Status |
| --- | --- | --- |
| jruby | 26.04 LTS resolute | Needs evaluation |
| 25.10 questing | Ignored end of life, was needs-triage |
| 25.04 plucky | Ignored end of life, was needs-triage |
| 24.10 oracular | Ignored end of life, was needs-triage |
| 24.04 LTS noble | Needs evaluation |
| 23.10 mantic | Ignored end of life, was needs-triage |
| 23.04 lunar | Ignored end of life, was needs-triage |
| 21.10 impish | Ignored end of life |
| 21.04 hirsute | Ignored end of life |
| 20.10 groovy | Ignored end of life |
| 20.04 LTS focal | Needs evaluation |
| 19.10 eoan | Ignored end of life |
| 19.04 disco | Ignored end of life |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |
| 14.04 LTS trusty | Fixed 1.5.6-9+deb8u2build0.14.04.1~esm2 Ubuntu Pro |
| ruby2.3 | 26.04 LTS resolute | Not in release |
| 25.10 questing | Not in release |
| 25.04 plucky | Not in release |
| 24.10 oracular | Not in release |
| 24.04 LTS noble | Not in release |
| 23.10 mantic | Not in release |
| 23.04 lunar | Not in release |
| 22.10 kinetic | Not in release |
| 22.04 LTS jammy | Not in release |
| 21.10 impish | Not in release |
| 21.04 hirsute | Not in release |
| 20.10 groovy | Not in release |
| 20.04 LTS focal | Not in release |
| 19.10 eoan | Not in release |
| 19.04 disco | Not in release |
| 18.04 LTS bionic | Not in release |
| 16.04 LTS xenial | Fixed 2.3.1-2~ubuntu16.04.14 |
| 14.04 LTS trusty | Not in release |
| ruby2.5 | 26.04 LTS resolute | Not in release |
| 25.10 questing | Not in release |
| 25.04 plucky | Not in release |
| 24.10 oracular | Not in release |
| 24.04 LTS noble | Not in release |
| 23.10 mantic | Not in release |
| 23.04 lunar | Not in release |
| 22.10 kinetic | Not in release |
| 22.04 LTS jammy | Not in release |
| 21.10 impish | Not in release |
| 21.04 hirsute | Not in release |
| 20.10 groovy | Not in release |
| 20.04 LTS focal | Not in release |
| 19.10 eoan | Fixed 2.5.5-4ubuntu2.1 |
| 19.04 disco | Fixed 2.5.5-1ubuntu1.1 |
| 18.04 LTS bionic | Fixed 2.5.1-1ubuntu1.6 |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
---
* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2019-16255?format=md#patch-details)
### Get expanded security coverage with Ubuntu Pro
Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use.
[Get Ubuntu Pro](https://ubuntu.com/pro)
[30-day free trial](https://ubuntu.com/pro/free-trial)
### Patch details
For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
| Package | Patch details |
| --- | --- |
| ruby2.5 | * Upstream: [3af01ae](https://github.com/ruby/ruby/commit/3af01ae1101e0b8815ae5a106be64b0e82a58640) |
## Severity score breakdown
CVSS version:
CVSS v3.0
**Base score**
8.1 · High
* Base metrics
| Parameter | Value |
| --- | --- |
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | High |
| Integrity impact | High |
| Availability impact | High |
* Scores
| Parameter | Value |
| --- | --- |
| Base score | 8.1 · High |
| Exploitability score | - |
| Impact score | - |
**Vector:** CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
## References
* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-16255)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2019-16255)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2019-16255)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2019-16255)
### Related Ubuntu Security Notices (USN)
+ [USN-4201-1](https://usn.ubuntu.com/USN-4201-1)
+ Ruby vulnerabilities
+ 26 November 2019
### Other references
*
*