CVE-2026-44318 free5GC: BSF concurrent PUT /nbsf-management/v1/subscriptions/{subId} crashes the BSF process via concurrent map read/write on Subscriptions

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's BSF PUT /nbsf-management/v1/subscriptions/subId handler has an unsynchronized write on the global Subscriptions map. The handler first reads the map under RLock via BSFContext.GetSubscriptionsubId, but if t...