CVE-2023-34450

CometBFT is a Byzantine Fault Tolerant (BFT) middleware that takes a state transition machine and replicates it on many machines. An internal modification made in versions 0.34.28 and 0.37.1 to the way struct PeerState is serialized to JSON introduced a deadlock when new function MarshallJSON is called. This function can be called from two places. The first is via logs, setting the consensus logging module to "debug" level (should not happen in production), and setting the log output format to JSON. The second is via RPC dump_consensus_state.

Case 1, which should not be hit in production, will eventually hit the deadlock in most goroutines, effectively halting the node.

In case 2, only the data structures related to the first peer will be deadlocked, together with the thread(s) dealing with the RPC request(s). This means that only one of the channels of communication to the node's peers will be blocked. Eventually the peer will timeout and excluded from the list (typically afte