• Component Type: TYPO3 CMS
• Subcomponent: Link Handling (ext:core, ext:frontend)
• Release Date: December 17, 2019
• Vulnerability Type: Cross-Site Scripting
• Affected Versions: 8.0.0-8.7.29 and 9.0.0-9.5.11 and 10.0.0-10.2.0
• Severity: Medium
• Suggested CVSS v3.1: AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C
• CVE: not assigned yet

Problem Description

It has been discovered that t3:// URL handling and typolink functionality are vulnerable to cross-site scripting. Not only regular backend forms are affected but also frontend extensions which use the rendering with typolink.

Solution

Update to TYPO3 versions 8.7.30 or 9.5.12 or 10.2.2 that fix the problem described.

Credits

Thanks to Oliver Hader who reported this issue and to TYPO3 framework mergers Susanne Moog, Oliver Hader and Frank Nägler who analyzed and fixed the issue.

General Advice

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

General Note

All security related code changes are tagged so that you can easily look them up in our review system.