In an authorization bypass attack, an attacker exploits vulnerabilities in poorly designed applications or login forms (e.g. client-side data input validation). Authentication modules shipped with the TYPO3 core are well-tested and reviewed. However, due to the open architecture of TYPO3, this system can be extended by alternative solutions. The code quality and security aspects may vary, see chapter “Guidelines for TYPO3 Integrators: TYPO3 extensions” for further details.