• Project: Joomla!
  • SubProject: CMS
  • Impact: Low
  • Severity: Low
  • Versions: 3.2.0 - 3.9.24
  • Exploit type: Insecure Randomness
  • Reported Date: 2021-01-12
  • Fixed Date: 2021-03-02
  • CVE Number: CVE-2021-23126CVE-2021-23127


Usage of the insecure rand() function within the process of generating the 2FA secret.
Usage of an insufficient length for the 2FA secret accoring to RFC 4226 of 10 bytes vs 20 bytes.

Additional details as well as a more contexts for exising sites can be found in the docs: https://docs.joomla.org/J3.x:Changes_to_the_2FA_token_generation_recommendations_for_existing_sites

This issue has been coordinated with Akeeba Ltd as contributor of the original FOF codebase to the core.

Affected Installs

Joomla! CMS versions 3.2.0 - 3.9.24


Upgrade to version 3.9.25


The JSST at the Joomla! Security Centre.

Reported By: Hanno Böck