CVE-2025-15528 is a denial of service vulnerability found in Open5GS, an open-source implementation of the 5G core network. The vulnerability affects versions 2.7.0 through 2.7.6 and resides in the GTPv2 Bearer Response Handler component. GTPv2 (GPRS Tunneling Protocol version 2) is critical for signaling and bearer management in 4G and 5G networks. The flaw allows an attacker to remotely send specially crafted messages to the vulnerable component, causing it to malfunction and crash or become unresponsive, resulting in denial of service. The attack requires no authentication or user interaction, increasing its risk profile. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P) indicates network attack vector, low attack complexity, no privileges or user interaction required, and low impact on availability. The vulnerability has been publicly disclosed, and a patch is available identified by the commit hash 98f76e98df35cd6a35e868aa62715db7f8141ac1. While no active exploitation in the wild has been reported, the public availability of the exploit code increases the likelihood of future attacks. Open5GS is widely used by telecom operators and research institutions for 5G core network deployments, making this vulnerability a significant concern for critical telecommunications infrastructure.

The primary impact of CVE-2025-15528 is denial of service against Open5GS 5G core network components, specifically the GTPv2 Bearer Response Handler. This can lead to service outages or degraded network performance, affecting subscriber connectivity and network reliability. Telecom operators using Open5GS may experience partial or full disruption of 5G core network functions, potentially impacting voice, data, and signaling services. Given the critical role of 5G core networks in modern communications, this can have cascading effects on emergency services, enterprise connectivity, and consumer mobile services. The vulnerability's ease of exploitation and lack of required authentication make it a viable attack vector for threat actors aiming to disrupt telecommunications infrastructure. While no known active exploitation is reported, the public disclosure of the exploit increases the risk of opportunistic attacks. Organizations relying on Open5GS must consider the operational and reputational risks associated with potential service interruptions.

To mitigate CVE-2025-15528, organizations should immediately apply the official patch identified by commit 98f76e98df35cd6a35e868aa62715db7f8141ac1 to all affected Open5GS deployments running versions 2.7.0 through 2.7.6. Network operators should conduct thorough testing in staging environments before production deployment to ensure stability. Additionally, implementing network-level protections such as filtering and rate limiting of GTPv2 traffic can reduce exposure to malformed packets. Monitoring network traffic for anomalies related to GTPv2 Bearer Response messages can help detect attempted exploitation. Employing intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability can provide additional defense layers. Operators should also maintain strict access controls and segmentation for core network components to limit attack surface. Regularly updating Open5GS and subscribing to security advisories will help promptly address future vulnerabilities. Finally, developing incident response plans specific to 5G core network disruptions will improve organizational readiness.