CVE-2022-23501 is a medium-severity vulnerability classified under CWE-287 (Improper Authentication) affecting multiple versions of TYPO3, an open-source PHP-based web content management system widely used for building and managing websites. The vulnerability exists in TYPO3 versions prior to 8.7.49, 9.5.38, 10.4.33, 11.5.20, and 12.1.1. It arises from a flaw in the frontend login mechanism where user access restrictions based on storage folders (partitions) can be bypassed. Specifically, TYPO3 allows organizing frontend users into different storage folders to restrict login access. However, due to ambiguous handling of usernames across these partitions, an attacker who already knows valid credentials for one user can exploit this ambiguity to gain access to a different user account residing in another storage folder. This bypass does not allow credential guessing or brute forcing but leverages the system's failure to properly enforce partition-based access controls during authentication. The vulnerability requires the attacker to have valid credentials for at least one user but enables lateral movement to other accounts without additional authentication. The issue has been patched in the specified versions, and no known exploits have been reported in the wild as of the publication date. The vulnerability impacts confidentiality and integrity by allowing unauthorized access to user accounts, potentially exposing sensitive data or enabling unauthorized actions within TYPO3-managed websites. Availability impact is limited as the vulnerability does not directly cause denial of service. Exploitation complexity is moderate since valid credentials are required, and user interaction is not needed beyond login attempts. The scope is limited to TYPO3 installations using frontend user storage folder restrictions, which is a common configuration in multi-tenant or segmented user environments.

For European organizations using TYPO3, especially those managing multiple user groups or tenants via storage folder partitions, this vulnerability poses a risk of unauthorized access to user accounts beyond the attacker's original privileges. This can lead to data leakage, unauthorized content modification, or privilege escalation within the CMS environment. Organizations in sectors such as government, education, media, and e-commerce that rely on TYPO3 for public-facing or internal websites may face reputational damage, regulatory compliance issues (e.g., GDPR violations due to data exposure), and operational disruptions. The impact is heightened in environments where user accounts have access to sensitive information or administrative functions. Since TYPO3 is popular in Europe, particularly in Germany and surrounding countries, the risk is non-trivial. However, the requirement for known credentials limits mass exploitation, making targeted attacks more likely. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially if attackers gain credentials through phishing or other means.

1. Immediate upgrade of TYPO3 installations to the patched versions: 8.7.49 ELTS, 9.5.38 ELTS, 10.4.33, 11.5.20, or 12.1.1 or later. 2. Review and audit frontend user storage folder configurations to ensure proper segmentation and minimize unnecessary cross-folder access. 3. Implement strong credential hygiene policies, including multi-factor authentication (MFA) where possible, to reduce the risk of credential compromise. 4. Monitor login activities for unusual patterns indicating potential lateral movement attempts between user accounts. 5. Limit the number of users with overlapping or ambiguous usernames across storage folders to reduce exploitation surface. 6. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious login attempts that may exploit this vulnerability. 7. Conduct regular security assessments and penetration testing focused on authentication mechanisms within TYPO3 deployments. 8. Educate users and administrators about phishing and credential theft risks to prevent attackers from obtaining valid credentials required for exploitation.