Executive brief
Open5GS is an open-source implementation of a 5G core network (the backbone infrastructure connecting cellular networks). A null pointer dereference vulnerability in the Access and Mobility Management Function (AMF) Transfer Endpoint could allow remote attackers to crash the service, disrupting mobile network connectivity and potentially affecting millions of subscribers depending on deployment scale.
Technical details
The vulnerability is a null pointer dereference in the file src/amf/namf-handler.c within the Transfer Endpoint component of Open5GS. The root cause involves improper handling of unknown NGAP IE types in the amf_namf_comm_handle_n1_n2_message_transfer function, which previously called ogs_assert_if_reached() in the default case, causing an immediate crash. The attack is network-reachable and does not require authentication. An attacker can send crafted N1/N2 message transfers to trigger the null pointer dereference, resulting in denial of service (process crash). The vulnerability affects Open5GS up to version 2.7.7; version 2.8.0 and later address this issue via patch abf8a83, which replaces the assertion with proper error handling.
Affected products
- Open5GS Open5GS up to 2.7.7
Timeline
- 2026-08-30: disclosed
- 2026-05-14: patched: Patch committed as abf8a83; fix included in version 2.8.0