CVE-2025-48205 is a vulnerability classified under CWE-425 (Direct Request or Forced Browsing) affecting the sr_feuser_register extension version 5.1.0 for the TYPO3 content management system (CMS). This extension is designed to manage frontend user registrations and related functionalities. The vulnerability allows an attacker to perform Insecure Direct Object Reference (IDOR), meaning they can directly access or manipulate objects or resources by modifying URL parameters or request data without proper authorization checks. The CVSS 3.1 base score is 8.6, indicating a high severity level, with the vector AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N. This means the attack can be performed remotely over the network without any privileges or user interaction, and it impacts confidentiality with a high impact, while integrity and availability remain unaffected. The scope is changed (S:C), indicating that the vulnerability affects resources beyond the initially intended security scope. The lack of known exploits in the wild suggests it is a recently disclosed vulnerability. TYPO3 is widely used in Europe, especially by public sector and medium to large enterprises, making this vulnerability significant. Attackers exploiting this flaw could gain unauthorized access to sensitive user data managed by the extension, potentially leading to data breaches or privacy violations. Since the vulnerability does not affect integrity or availability, the main risk is unauthorized data disclosure through forced browsing techniques, where attackers enumerate or guess resource identifiers to access restricted data. The absence of patches at the time of disclosure requires organizations to implement compensating controls promptly.

For European organizations using TYPO3 with the sr_feuser_register extension, this vulnerability poses a significant risk to user data confidentiality. Many European public institutions, educational organizations, and businesses rely on TYPO3 for their web presence and user management. Exploitation could lead to unauthorized disclosure of personal data, potentially violating GDPR and other data protection regulations, resulting in legal and financial repercussions. The vulnerability's remote exploitability without authentication increases the risk of automated scanning and mass exploitation attempts. Given the scope change, attackers might access data beyond their privilege level, amplifying the impact. The lack of impact on integrity and availability reduces risks of data tampering or service disruption but does not mitigate the serious privacy concerns. Organizations could face reputational damage and loss of user trust if breaches occur. The threat is particularly relevant for sectors handling sensitive personal or customer data, such as healthcare, government, and finance within Europe.

1. Immediate mitigation should include restricting access to the sr_feuser_register extension's sensitive endpoints via web application firewalls (WAF) or access control lists (ACLs) to trusted IP ranges where feasible. 2. Implement strict server-side authorization checks to validate user permissions before granting access to any user-related resources, even if the extension does not yet provide patches. 3. Monitor web server logs for unusual patterns indicative of forced browsing attempts, such as sequential or random access to user resource identifiers. 4. Disable or remove the sr_feuser_register extension if it is not essential to reduce the attack surface until a patch is available. 5. Keep TYPO3 core and all extensions updated regularly and subscribe to TYPO3 security advisories for timely patch releases. 6. Conduct a thorough audit of user data exposure and review compliance with GDPR data minimization and access principles. 7. Educate development and security teams about IDOR vulnerabilities and enforce secure coding practices to prevent similar issues in custom extensions.