TYPO3-EXT-SA-2021-006: Server-side request forgery in extension "Yoast SEO for TYPO3" (yoast_seo)

Categories: Development, Security Created by Torben Hansen
It has been discovered that the extension "Yoast SEO for TYPO3" (yoast_seo) is susceptible to Server-side request forgery (SSRF).
  • Release Date: April 27, 2021
  • Component Type: Third party extension. This extension is not a part of the TYPO3 default installation.
  • Component: "Yoast SEO for TYPO3" (yoast_seo)
  • Vulnerability Type: Server-side request forgery
  • Affected Versions: 7.2.0 and below
  • Severity: Medium
  • Suggested CVSS: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N/E:F/RL:O/RC:C
  • References: CVE-2021-31779

Problem Description

The extension fails to restrict analyzed URLs to domains managed by the current TYPO3 website. A logged in TYPO3 backend user can use the vulnerability to make HTTP requests to arbitrary domains including the webserver itself or other internally managed resources.


An updated version 7.2.1  is available from the TYPO3 extension manager, Packagist and at
Users of the extension are advised to update the extension as soon as possible.


Thanks to Andrey Basarygin, Andrey Guzei, Mikhail Khramenkov, Alexander Sidukov and Maxim Teplykh from Solar Security  for reporting the issue and to MaxServ BV for providing an updated version of the extension.

General Advice

Follow the recommendations that are given in the TYPO3 Security Guide. Please subscribe to the typo3-announce mailing list.