CVE-2025-15532 is a vulnerability identified in Open5GS, an open-source 5G core network implementation widely used for mobile network infrastructure. The flaw resides in the Timer Handler component, where certain processing can be manipulated remotely to cause excessive resource consumption. This type of vulnerability typically leads to denial of service (DoS) conditions by exhausting CPU, memory, or other critical resources, thereby degrading or interrupting service availability. The vulnerability affects Open5GS versions 2.7.0 through 2.7.5. Exploitation requires no authentication or user interaction and can be performed remotely, increasing the attack surface. Although the exact technical details of the Timer Handler manipulation are unspecified, the public availability of an exploit increases the risk of active attacks. The issue was assigned a CVSS 4.0 score of 6.9, indicating a medium severity level primarily due to the potential for resource exhaustion and service disruption without compromising confidentiality or integrity. A patch identified by commit c7c131f8d2cb1195ada5e0e691b6868ebcd8a845 has been released to remediate the flaw. Open5GS is critical in 5G network deployments, handling core network functions such as session management and mobility management, making this vulnerability particularly relevant to telecom operators and infrastructure providers.

For European organizations, especially telecom operators and 5G infrastructure providers, this vulnerability poses a risk of service disruption through denial of service attacks. Exploitation could lead to degraded network performance or outages affecting end-users and enterprise customers relying on 5G connectivity. This can impact critical communications, IoT services, and business operations dependent on mobile networks. The resource consumption attack could also increase operational costs due to the need for incident response and potential hardware scaling to mitigate effects. Given the remote and unauthenticated nature of the exploit, attackers can launch attacks from outside the network perimeter, increasing the threat landscape. Disruptions in 5G core networks can have cascading effects on emergency services, industrial automation, and smart city applications prevalent in Europe. The medium severity rating suggests moderate impact but with significant operational consequences if exploited at scale.

Organizations should immediately apply the patch identified by commit c7c131f8d2cb1195ada5e0e691b6868ebcd8a845 to all affected Open5GS instances. Beyond patching, network operators should implement rate limiting and anomaly detection on traffic directed at the Timer Handler or related components to identify and block abnormal resource consumption patterns. Deploying network segmentation and strict access controls can reduce exposure of Open5GS management interfaces to untrusted networks. Continuous monitoring of resource utilization metrics and alerting on spikes can provide early warning of exploitation attempts. Conducting regular vulnerability assessments and penetration testing focused on 5G core components will help identify residual risks. Additionally, operators should maintain incident response plans tailored to 5G infrastructure to minimize downtime in case of attacks. Collaboration with vendors and sharing threat intelligence within European telecom communities can enhance preparedness.