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             AUSCERT External Security Bulletin Redistribution

                     USN-5020-1: Ruby vulnerabilities
                               22 July 2021


        AusCERT Security Bulletin Summary

Product:           Ruby
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account      
                   Unauthorised Access             -- Remote/Unauthenticated
                   Reduced Security                -- Remote/Unauthenticated
                   Provide Misleading Information  -- Unknown/Unspecified   
                   Access Confidential Data        -- Unknown/Unspecified   
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-32066 CVE-2021-31810 CVE-2021-31799

Reference:         ESB-2021.2338

Original Bulletin: 

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USN-5020-1: Ruby vulnerabilities
21 July 2021

Several security issues were fixed in Ruby.

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


  o ruby2.3 - Object-oriented scripting language
  o ruby2.5 - Object-oriented scripting language
  o ruby2.7 - Object-oriented scripting language


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

Ubuntu 21.04

  o ruby2.7 - 2.7.2-4ubuntu1.2
  o libruby2.7 - 2.7.2-4ubuntu1.2

Ubuntu 20.10

  o ruby2.7 - 2.7.1-3ubuntu1.4
  o libruby2.7 - 2.7.1-3ubuntu1.4

Ubuntu 20.04

  o ruby2.7 - 2.7.0-5ubuntu1.5
  o libruby2.7 - 2.7.0-5ubuntu1.5

Ubuntu 18.04

  o ruby2.5 - 2.5.1-1ubuntu1.10
  o libruby2.5 - 2.5.1-1ubuntu1.10

Ubuntu 16.04

  o libruby2.3 - 2.3.1-2~ubuntu16.04.16+esm1
    Available with UA Infra or UA Desktop
  o ruby2.3 - 2.3.1-2~ubuntu16.04.16+esm1
    Available with UA Infra or UA Desktop

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


  o CVE-2021-31799
  o CVE-2021-32066
  o CVE-2021-31810

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