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Ubuntu Security Notice USN-5020-1
July 21, 2021

ruby2.3, ruby2.5, ruby2.7 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 21.04
- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in Ruby.

Software Description:
- ruby2.7: Object-oriented scripting language
- ruby2.5: Object-oriented scripting language
- ruby2.3: Object-oriented scripting language

Details:

It was discovered that Ruby incorrectly handled certain inputs.
An attacker could possibly use this issue to execute arbitrary code.
(CVE-2021-31799)

It was discovered that Ruby incorrectly handled certain inputs.
An attacker could possibly use this issue to conduct
port scans and service banner extractions. This issue only affected
Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 20.10, and Ubuntu 21.04. (CVE-2021-31810)

It was discovered that Ruby incorrectly handled certain inputs.
An attacker could possibly use this issue to perform
man-in-the-middle attackers to bypass the TLS protection.
(CVE-2021-32066)

Update instructions:

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

Ubuntu 21.04:
  libruby2.7                      2.7.2-4ubuntu1.2
  ruby2.7                         2.7.2-4ubuntu1.2

Ubuntu 20.10:
  libruby2.7                      2.7.1-3ubuntu1.4
  ruby2.7                         2.7.1-3ubuntu1.4

Ubuntu 20.04 LTS:
  libruby2.7                      2.7.0-5ubuntu1.5
  ruby2.7                         2.7.0-5ubuntu1.5

Ubuntu 18.04 LTS:
  libruby2.5                      2.5.1-1ubuntu1.10
  ruby2.5                         2.5.1-1ubuntu1.10

Ubuntu 16.04 ESM:
  libruby2.3                      2.3.1-2~ubuntu16.04.16+esm1
  ruby2.3                         2.3.1-2~ubuntu16.04.16+esm1

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

References:
  https://ubuntu.com/security/notices/USN-5020-1
  CVE-2021-31799, CVE-2021-31810, CVE-2021-32066

Package Information:
  https://launchpad.net/ubuntu/+source/ruby2.7/2.7.2-4ubuntu1.2
  https://launchpad.net/ubuntu/+source/ruby2.7/2.7.1-3ubuntu1.4
  https://launchpad.net/ubuntu/+source/ruby2.7/2.7.0-5ubuntu1.5
  https://launchpad.net/ubuntu/+source/ruby2.5/2.5.1-1ubuntu1.10