MongoDb NULL Pointer Dereference Vulnerability - CVE-2026-8063

An authenticated user can crash mongod when running rankFusion or scoreFusion with an empty pipeline on a view. When resolving a view the server inspects the aggregation pipeline to determine whether it begins with an Atlas Search stage. For rankFusion and scoreFusion this inspection reads the first element on each stages input pipeline array without first verifying that the array is non-empty. Supplying an empty pipeline causes a null pointer dereference and crashes the server. This issue affects MongoDB Server 8.2 versionsprior to 8.2.7.