TYPO3-EXT-SA-2021-016: Denial of Service in extension "Code Highlight" (codehighlight)

Categories: Development, Security Created by Torben Hansen
It has been discovered that the extension "Code Highlight" (codehighlight) is susceptible to Denial of Service.
  • Release Date: November 10, 2021
  • Component Type: Third party extension. This extension is not a part of the TYPO3 default installation.
  • Component: "Code Highlight" (codehighlight)
  • Vulnerability Type: Denial of Service
  • Affected Versions: 2.6.0 and below
  • Severity: Medium
  • Suggested CVSS: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L/E:F/RL:O/RC:C
  • References: N/A

Problem Description

The extension bundles a vulnerable version of the 3rd party JavaScript component “prism” which is known to be vulnerable against Regular expression Denial of Service (ReDoS).


An updated version 2.7.0  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 Chris Müller for reporting the issue and 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.