---
title: "CVE-2019-16254\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-2019-16254?format=md
keywords: index, follow
---

# CVE-2019-16254

Publication date 20 November 2019

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**5.3 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2019-16254?format=md#impact-score)

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## Description

Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 allows
HTTP Response Splitting. If a program using WEBrick inserts untrusted input
into the response header, an attacker can exploit it to insert a newline
character to split a header, and inject malicious content to deceive
clients. NOTE: this issue exists because of an incomplete fix for
CVE-2017-17742, which addressed the CRLF vector, but did not address an
isolated CR or an isolated LF.

### From the Ubuntu Security Team

It was discovered that JRuby mishandled newline characters in HTTP response
headers. A remote attacker could use this vulnerability to display malicious
content to HTTP clients.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| jruby | 21.10 impish | Not affected |
| 21.04 hirsute | Not affected |
| 20.10 groovy | Not affected |
| 20.04 LTS focal | Not affected |
| 19.10 eoan | Ignored end of life |
| 19.04 disco | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Fixed 1.5.6-9+deb8u2build0.14.04.1~esm2  Ubuntu Pro |
| ruby2.3 | 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 | 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-2019-16254?format=md#patch-details)

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### 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:   [3ce238b](https://github.com/ruby/ruby/commit/3ce238b5f9795581eb84114dcfbdf4aa086bfecc) * Upstream:   [f98b302](https://github.com/ruby/ruby/commit/f98b3023bd786b4e7dfdb94b573a5f5d3d37d145) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

5.3 · Medium

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 5.3 · Medium |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-16254)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2019-16254)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2019-16254)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2019-16254)

### Related Ubuntu Security Notices (USN)

+ [USN-4201-1](https://usn.ubuntu.com/USN-4201-1)
+ Ruby vulnerabilities
+ 26 November 2019

### Other references

* <https://www.ruby-lang.org/en/news/2019/10/01/http-response-splitting-in-webrick-cve-2019-16254/>
* <https://www.cve.org/CVERecord?id=CVE-2019-16254>