A flaw in Open5GS up to version 2.7.7 allows an attacker to manipulate the ipv6Prefix argument to the bsf_sess_find_by_ipv6prefix function in the BSF context module, triggering a denial of service failure. The vulnerability is a classic resource exhaustion issue, known as CWE‑404, where improper handling of the prefix leads to exhaustion of internal session resources and service disruption.

The issue affects the Open5GS project, specifically the BSF component. All Open5GS deployments running any version up to 2.7.7 are potentially impacted. No specific sub‑versions are listed beyond this upper bound; therefore, any installation of Open5GS between the initial release and 2.7.7 should be considered vulnerable.

The CVSS score of 5.3 places this vulnerability in the medium severity range. The EPSS score is not available, and it is not listed in the CISA KEV catalog. The attack can be initiated remotely, and the exploit code has already been published, indicating realistic exploitation potential. Without patching or mitigating controls, an attacker can cause sustained denial of service to the BSF service, potentially disrupting user plane connectivity for affected networks.