CVE-2026-1586 identifies a denial of service (DoS) vulnerability in Open5GS, an open-source 5G core network implementation widely used for mobile network infrastructure. The vulnerability resides in the ogs_gtp2_f_teid_to_ip function within the SGWC (Serving Gateway Control) component, specifically in the s11-handler.c source file. This function is responsible for translating GTP (GPRS Tunneling Protocol) Tunnel Endpoint Identifiers (TEIDs) to IP addresses during signaling message processing. Improper handling or validation of manipulated input data can cause the function to malfunction, leading to a crash or hang of the SGWC process. The attack vector is remote and does not require any authentication or user interaction, making exploitation relatively straightforward for an attacker with network access to the affected component. The CVSS 4.0 base score is 6.9 (medium severity), reflecting the network attack vector, low complexity, and lack of required privileges, but limited to availability impact only. The vulnerability affects Open5GS versions 2.7.0 through 2.7.5 and has been addressed in subsequent releases. While no active exploitation has been reported, a proof-of-concept exploit is publicly available, increasing the risk of future attacks. Open5GS is commonly deployed by telecom operators and enterprises implementing private 5G networks, making this vulnerability relevant to critical telecommunications infrastructure.

The primary impact of CVE-2026-1586 is denial of service, which can disrupt the availability of the 5G core network components relying on Open5GS. This disruption can cause service outages, dropped connections, and degraded network performance for end users. For telecom operators, this can translate into customer dissatisfaction, regulatory penalties, and financial losses. Enterprises using Open5GS for private 5G networks may experience operational interruptions affecting business-critical applications. Since the vulnerability can be exploited remotely without authentication, attackers can launch DoS attacks from within or near the network perimeter, potentially causing widespread service degradation. The scope is limited to availability, with no direct confidentiality or integrity compromise reported. However, prolonged outages in 5G core infrastructure can indirectly affect other dependent services and emergency communications. The presence of a public exploit increases the urgency to remediate before attackers weaponize the flaw.

Organizations should immediately upgrade Open5GS to the latest version that includes the patch for CVE-2026-1586. If immediate upgrade is not feasible, applying any available vendor-provided patches or workarounds is critical. Network administrators should implement strict filtering and validation of GTP traffic, especially on the S11 interface, to block malformed or suspicious packets that could trigger the vulnerability. Deploying intrusion detection/prevention systems (IDS/IPS) with signatures targeting this exploit can help detect and mitigate attack attempts. Network segmentation and limiting access to the SGWC component to trusted sources reduce exposure. Monitoring system logs and network traffic for anomalies related to GTP signaling can provide early warning of exploitation attempts. Regular security assessments and penetration testing of 5G core components are recommended to identify and remediate similar vulnerabilities proactively.