CVE-2025-69250 is a vulnerability classified under CWE-754, indicating improper checks for unusual or exceptional conditions within the free5gc UDM component, which is part of the open-source 5G core network implementation free5GC. Specifically, in versions up to and including 1.4.1, the UDM service leaks detailed internal error messages when processing invalid pduSessionId inputs in the Nudm_UECM DELETE service. These error messages include parsing errors such as strconv.ParseInt failures, which reveal internal implementation details to unauthenticated remote clients. This leakage can be exploited for service fingerprinting, allowing attackers to gain insight into the backend system's behavior and potentially identify further attack vectors. The vulnerability does not require any privileges or user interaction, making it remotely exploitable over the network. The issue arises from insufficient validation and error handling logic that fails to suppress or generalize error messages before sending them to clients. The free5gc project has addressed this vulnerability in pull request 76, which corrects the error handling to prevent detailed error disclosure. No direct workaround exists at the application level, so applying the official patch is the recommended remediation. The CVSS 4.0 vector (AV:N/AC:L/PR:N/UI:N/VC:H/VI:N/VA:N) reflects a network attack vector with low complexity, no privileges or user interaction required, and high confidentiality impact due to information disclosure, but no impact on integrity or availability.

The primary impact of CVE-2025-69250 is information disclosure through detailed error message leakage. This can aid attackers in fingerprinting the free5gc UDM service, revealing internal implementation details such as parsing logic and error handling behavior. Such reconnaissance can facilitate more targeted attacks against the 5G core network infrastructure, potentially leading to exploitation of other vulnerabilities or unauthorized access. Although this vulnerability does not directly compromise data integrity or availability, the exposure of internal error details weakens the security posture and increases the attack surface. Organizations deploying free5GC UDM in their 5G core networks may face increased risk of targeted attacks, especially from advanced persistent threats or nation-state actors interested in telecommunications infrastructure. Given the critical role of UDM in subscriber data management and authentication within 5G networks, any compromise or reconnaissance advantage can have significant downstream effects on network security and user privacy.

To mitigate CVE-2025-69250, organizations should promptly apply the official patch provided in free5gc/udm pull request 76, which corrects the error handling logic to prevent detailed error message leakage. Since no direct application-level workaround is available, patching is the primary remediation step. Additionally, organizations should implement network-level protections such as restricting access to the Nudm_UECM DELETE service to trusted management networks or VPNs to reduce exposure to unauthenticated remote clients. 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 and block exploitation attempts. Regularly auditing and monitoring logs for unusual error message patterns or repeated invalid pduSessionId requests can provide early warning of reconnaissance activity. Finally, maintaining an up-to-date inventory of free5GC components and versions deployed across the network will facilitate timely patch management and vulnerability response.