TYPO3-CORE-SA-2020-004: Class destructors causing side-effects when being unserialized

Categories: Development Created by Oliver Hader
It has been discovered that TYPO3 CMS is vulnerable to insecure deserialization.

Problem Description

Calling unserialize() on malicious user-submitted content can result in the following scenarios:

  • trigger deletion of arbitrary directory in file system (if writable for web server)
  • trigger message submission via email using identity of web site (mail relay)

Another insecure deserialization vulnerability is required to actually exploit mentioned aspects.


Update to TYPO3 versions 9.5.17 or 10.4.2 that fix the problem described.


Thanks to TYPO3 security team member Oliver Hader who reported 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

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