CVE-2025-7485 is a medium-severity vulnerability identified in Open5GS, an open-source 5G core network implementation widely used for mobile network infrastructure. The vulnerability affects versions 2.7.0 through 2.7.3 and resides in the SCTP Partial Message Handler component, specifically within the functions ngap_recv_handler, s1ap_recv_handler, and recv_handler. These functions handle incoming signaling messages over SCTP (Stream Control Transmission Protocol), which is critical for communication between network elements in 5G core networks. The vulnerability manifests as a reachable assertion failure triggered by crafted local input, which can cause the affected process to abort unexpectedly. This reachable assertion indicates that under certain conditions, the software encounters an unexpected state that leads to a forced termination, potentially causing denial of service (DoS). Exploitation requires local access with low privileges and does not require user interaction or elevated authentication. The CVSS 4.0 vector (AV:L/AC:L/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X) reflects that the attack vector is local, with low complexity, low privileges, no user interaction, and limited impact on confidentiality, integrity, and availability. No known exploits are currently in the wild, and a patch identified by commit cfa44575020f3fb045fd971358442053c8684d3d has been released to address the issue. Given the critical role of Open5GS in 5G network infrastructure, this vulnerability could disrupt signaling processes and network stability if exploited.

For European organizations, particularly telecom operators and infrastructure providers deploying Open5GS, this vulnerability poses a risk of service disruption through denial of service attacks. Although exploitation requires local access, which limits remote attack feasibility, insider threats or compromised internal systems could leverage this vulnerability to cause network outages or degrade service quality. Disruptions in 5G core network signaling can affect subscriber connectivity, impacting critical services reliant on mobile networks, including emergency communications, IoT deployments, and enterprise connectivity. The limited impact on confidentiality and integrity reduces the risk of data breaches, but availability degradation in telecom infrastructure can have cascading effects on dependent sectors. European telecom operators adopting Open5GS for private or public 5G networks should prioritize patching to maintain network reliability and comply with regulatory requirements for network security and resilience.

Specific mitigation steps include: 1) Immediate application of the official patch (commit cfa44575020f3fb045fd971358442053c8684d3d) to all affected Open5GS instances running versions 2.7.0 to 2.7.3. 2) Restrict local access to Open5GS servers by enforcing strict access controls, network segmentation, and monitoring to prevent unauthorized local exploitation. 3) Implement robust internal security monitoring to detect anomalous behavior or crashes related to SCTP message handling. 4) Conduct thorough testing of patched systems in staging environments to ensure stability before production deployment. 5) Regularly update Open5GS to the latest stable versions beyond 2.7.3 to benefit from ongoing security improvements. 6) Incorporate security awareness training for administrators and operators regarding local threat vectors and the importance of patch management. 7) Employ redundancy and failover mechanisms in 5G core network components to minimize service impact in case of unexpected process termination.