The flaw exists in the _gtpv1_u_recv_cb function of the UPF component of Open5GS and allows an attacker to trigger uncontrolled resource consumption by sending manipulated GTPv1‑U packets. The vulnerability aligns with CWE‑400 (Uncontrolled Resource Consumption) and CWE‑404 (Improper Resource Control), resulting in excessive CPU or memory use that can degrade or crash the UPF service, effectively denying service to legitimate users.

Open5GS versions up to and including 2.7.7 are affected. The vulnerability resides in the UPF (User Plane Function) code located in src/upf/gtp-path.c and applies to installations that expose GTP‑U traffic to the network.

With a CVSS score of 6.9 the vulnerability is categorized as medium severity, and its EPSS score is currently not available. It is not listed in CISA’s KEV catalog. The attack vector is inferred to be remote, as the description states the attack may be performed from a remote source. An attacker can craft malformed GTPv1‑U messages directed at the UPF and force it to allocate resources until exhaustion, leading to a denial of service. No additional exploitation prerequisites beyond sending crafted GTP traffic are documented in the current description.