Pimcore is an Open Source Data & Experience Management Platform. Prior to 11.5.17 (LTS) and 12.3.7, multiple Pimcore locations call PHP's unserialize() on data from database columns and filesystem files without the allowed_classes restriction, including lib/Tool/Authentication.php, models/Site/Dao.php, models/DataObject/ClassDefinition/CustomLayout/Dao.php, models/Tool/TmpStore/Dao.php, models/Asset/WebDAV/Service.php, and admin-ui-classic-bundle/src/Helper/Dashboard.php, enabling object injection and remote code execution if an attacker can control the serialized data source. This issue is fixed in versions 11.5.17 (LTS) and 12.3.7.
https://github.com/pimcore/pimcore/security/advisories/GHSA-36fc-7wjg-mfvj
https://github.com/pimcore/pimcore/releases/tag/v12.3.7
https://github.com/pimcore/pimcore/pull/19119
https://github.com/pimcore/pimcore/commit/4788bf3a3a7f2f760a8fe61e522565941e154e1e