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Ubuntu Security Notice USN-7709-1
August 21, 2025

ruby-webrick vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 25.04
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS

Summary:

WEBrick could allow an HTTP request smuggling attack.

Software Description:
- ruby-webrick: HTTP server toolkit in Ruby

Details:

It was discovered that WEBrick incorrectly parsed HTTP headers. In
configurations where WEBrick is placed behind an HTTP proxy, a remote
attacker could possibly use this issue to perform an HTTP Request Smuggling
attack.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 25.04
  ruby-webrick                    1.8.1-1ubuntu1.1

Ubuntu 24.04 LTS
  ruby-webrick                    1.8.1-1ubuntu0.2

Ubuntu 22.04 LTS
  ruby-webrick                    1.7.0-3ubuntu0.2

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-7709-1
  CVE-2025-6442

Package Information:
  https://launchpad.net/ubuntu/+source/ruby-webrick/1.8.1-1ubuntu1.1
  https://launchpad.net/ubuntu/+source/ruby-webrick/1.8.1-1ubuntu0.2
  https://launchpad.net/ubuntu/+source/ruby-webrick/1.7.0-3ubuntu0.2