CVE-2025-69253 is a vulnerability classified under CWE-209 (Generation of Error Message Containing Sensitive Information) affecting the free5GC open-source 5G core network project, specifically the User Data Repository (udr) component up to version 1.4.1. The flaw arises from improper error handling in the Network Exposure Function (NEF) component, which leaks detailed internal parsing error messages to unauthenticated remote clients. For example, error messages may reveal specific parsing failures such as invalid characters encountered during JSON processing (e.g., 'invalid character 'n' after top-level value'). This leakage occurs when using the Nnef_PfdManagement service, which is part of the NEF interface responsible for managing policy flow descriptions. Such detailed error information can be exploited by attackers to fingerprint the service implementation, identify software versions, and potentially discover additional vulnerabilities or misconfigurations. The vulnerability has a CVSS 4.0 base score of 6.6, reflecting medium severity with network attack vector, no required privileges or user interaction, and high impact on confidentiality due to information exposure. The vulnerability was publicly disclosed on February 24, 2026, with no known active exploits. The free5GC project has addressed the issue in pull request 56 for the udr component, providing a patch that suppresses or sanitizes error messages to prevent sensitive information leakage. No direct workaround exists at the application level, making patching the primary mitigation strategy.

The primary impact of CVE-2025-69253 is the exposure of sensitive internal error details to unauthenticated remote attackers. This information leakage can facilitate service fingerprinting, allowing attackers to identify the exact version and configuration of the free5GC udr component in use. Such reconnaissance can be leveraged to tailor further attacks, including exploitation of other vulnerabilities or targeted denial-of-service attempts. While the vulnerability does not directly allow code execution or data manipulation, the confidentiality breach can undermine the security posture of 5G core network deployments. Given that free5GC is used in 5G mobile core networks, affected organizations include telecom operators, infrastructure providers, and enterprises deploying private 5G networks. Exploitation could lead to increased risk of subsequent attacks on critical telecommunications infrastructure, potentially impacting service availability and user privacy. The lack of authentication or user interaction requirements makes the attack vector broad and accessible to remote adversaries. However, the impact is somewhat limited by the nature of the information disclosed, which is primarily useful for reconnaissance rather than immediate exploitation.

To mitigate CVE-2025-69253, organizations should apply the official patch provided by the free5GC project in pull request 56 for the udr component as soon as possible. This patch addresses the improper error handling by sanitizing or suppressing detailed parsing error messages exposed to remote clients. Since no direct application-level workaround exists, patching is the only effective remediation. Additionally, organizations should implement network-level protections such as restricting access to the NEF interfaces, especially the Nnef_PfdManagement service, to trusted management networks or via VPNs to reduce exposure to unauthenticated attackers. Employing Web Application Firewalls (WAFs) or Intrusion Detection/Prevention Systems (IDS/IPS) with signatures tuned to detect anomalous requests or error message patterns can help detect exploitation attempts. Regularly monitoring logs for unusual error message requests or repeated parsing failures can provide early warning signs of reconnaissance activity. Finally, maintaining up-to-date inventories of free5GC components and versions deployed across the network will facilitate timely vulnerability management and patch deployment.