CVE-2024-25120 is a medium-severity vulnerability affecting TYPO3, an open-source PHP-based web content management system widely used for building and managing websites. The vulnerability arises from the TYPO3-specific URI scheme `t3://`, which is intended to reference internal resources such as files, folders, pages, and records within the CMS. Due to improper access control (CWE-284) and exposure of sensitive information (CWE-200), this URI scheme can be exploited by an attacker with a valid backend user account to access resources outside their authorized permission scope. This means that even users with limited backend privileges could potentially retrieve sensitive files or data they should not have access to, provided the TYPO3 installation has a valid link-handling configuration that enables this behavior. The vulnerability affects multiple TYPO3 versions, specifically all versions from 8.0.0 up to but not including the patched versions 8.7.57 ELTS, 9.5.46 ELTS, 10.4.43 ELTS, 11.5.35 LTS, 12.4.11 LTS, and 13.0.1. Exploitation requires authenticated backend access, which limits the attack vector to insiders or compromised accounts rather than anonymous external attackers. No known workarounds exist, and the only remediation is to update TYPO3 to one of the fixed versions. There are no reports of active exploitation in the wild as of the publication date. The vulnerability could lead to unauthorized disclosure of sensitive information, potentially including configuration files, user data, or internal content, which could facilitate further attacks or data breaches if leveraged by malicious actors.

For European organizations using TYPO3, this vulnerability poses a risk primarily to the confidentiality of sensitive information stored within the CMS environment. Since exploitation requires valid backend credentials, the threat is significant in scenarios where user accounts are compromised or where insider threats exist. Unauthorized access to sensitive files or records could lead to data leakage, intellectual property theft, or exposure of personal data subject to GDPR regulations, potentially resulting in regulatory penalties and reputational damage. The integrity and availability of the system are less directly impacted by this vulnerability, but the exposure of sensitive information could enable attackers to plan more damaging attacks such as privilege escalation or targeted phishing. Organizations in sectors with high regulatory scrutiny or those managing sensitive content—such as government, healthcare, finance, and media—are particularly at risk. The lack of known exploits in the wild suggests that immediate widespread impact is limited, but the vulnerability should be addressed promptly to prevent future exploitation.

1. Immediate upgrade of TYPO3 installations to the fixed versions listed (8.7.57 ELTS, 9.5.46 ELTS, 10.4.43 ELTS, 11.5.35 LTS, 12.4.11 LTS, or 13.0.1) is the only effective mitigation. 2. Conduct a thorough audit of backend user accounts to ensure that only necessary personnel have access, and enforce strong authentication mechanisms including multi-factor authentication (MFA) to reduce the risk of credential compromise. 3. Review and tighten backend user permissions to follow the principle of least privilege, minimizing the number of users with access to sensitive resources. 4. Monitor backend access logs for unusual activity or access patterns that could indicate exploitation attempts. 5. Implement network segmentation and access controls to limit backend access to trusted networks and devices. 6. Educate administrators and users with backend access about the risks of credential sharing and phishing attacks. 7. Regularly back up TYPO3 data and configurations to enable recovery in case of compromise. 8. Consider deploying web application firewalls (WAF) with custom rules to detect and block suspicious `t3://` URI requests if feasible, although this is a supplementary measure and not a replacement for patching.