A Null pointer dereference vulnerability in the Mobile Management Entity (MME) in Magma <= 1.8.0 (fixed in v1.9 commit 08472ba98b8321f802e95f5622fa90fec2dea486) allows network-adjacent attackers to crash the MME via an S1AP S1Setup Request packet missing an expected Global eNB ID field.
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.