CVE-2019-16254: Medium severity ruby-lang Ruby vulnerability

Published Oct 25, 2019
·
Updated

Last updated 25 August 2025

Other sources

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.

Affected Software

12 affected componentsFixes available
redhat/rh-ruby25-ruby<0:2.5.9-9.el7
0:2.5.9-9.el7
redhat/rh-ruby26-ruby<0:2.6.7-119.el7
0:2.6.7-119.el7
redhat/ruby<2.4.8
2.4.8
redhat/ruby<2.5.7
2.5.7
redhat/ruby<2.6.5
2.6.5
redhat/ruby<2.7.0
2.7.0
ruby-lang Ruby<=2.3.0
ruby-lang Ruby>=2.4.0<=2.4.7
ruby-lang Ruby>=2.5.0<=2.5.6
ruby-lang Ruby>=2.6.0<=2.6.4
Debian Debian Linux=8.0
debian/jruby
9.3.9.0+ds-89.4.8.0+ds-3

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/rh-ruby25-ruby to a version that resolves this vulnerability.

    Fixed in 0:2.5.9-9.el7
  2. Upgrade

    Upgrade redhat/rh-ruby26-ruby to a version that resolves this vulnerability.

    Fixed in 0:2.6.7-119.el7
  3. Upgrade

    Upgrade debian/jruby to a version that resolves this vulnerability.

    Fixed in 9.3.9.0+ds-8Fixed in 9.4.8.0+ds-3
  4. Upgrade

    Upgrade redhat/ruby to a version that resolves this vulnerability.

    Fixed in 2.4.8
  5. Upgrade

    Upgrade redhat/ruby to a version that resolves this vulnerability.

    Fixed in 2.5.7
  6. Upgrade

    Upgrade redhat/ruby to a version that resolves this vulnerability.

    Fixed in 2.6.5
  7. Upgrade

    Upgrade redhat/ruby to a version that resolves this vulnerability.

    Fixed in 2.7.0

Event History

Oct 25, 2019
CVE Published
12:00 AM
Nov 26, 2019
CVE Published
via MITRE·12:00 AM
Data Sourced
via MITRE·12:00 AM
Description
Data Sourced
via NVD·06:15 PM
DescriptionSeverityWeaknessAffected Software
Jan 9, 2020
Data Sourced
via Red Hat·07:38 PM
DescriptionSeverityAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is CVE-2019-16254?

CVE-2019-16254 is a vulnerability in Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 that allows HTTP Response Splitting.

2

How does CVE-2019-16254 work?

If an attacker inserts untrusted input into the response header of a program using WEBrick, they can exploit the vulnerability to insert a newline character and inject malicious content to deceive clients.

3

What is the severity of CVE-2019-16254?

CVE-2019-16254 has a severity rating of medium with a CVSS score of 5.3.

4

Which versions of Ruby are affected by CVE-2019-16254?

Ruby versions 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 are affected by CVE-2019-16254.

5

How can I fix CVE-2019-16254?

To fix CVE-2019-16254, update Ruby to version 2.4.8, 2.5.7, or 2.6.5 or later as appropriate for your version.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203