A NULL Pointer Dereference vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS).
When Layer 2 traffic is sent through a logical interface, MAC learning happens. If during this process, the interface flaps, an Advanced Forwarding Toolkit manager (evo-aftmand-bt) core is observed. This leads to a PFE restart. The crash reoccurs if the same sequence of events happens, which will lead to a sustained DoS condition.
This issue affects Juniper Networks Junos OS Evolved: 23.2-EVO versions earlier than 23.2R1-S1-EVO, 23.2R2-EVO.
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.