| Package | Affected versions | Patched versions |
|---|---|---|
| github.com/cometbft/cometbft | ≥ 0.34.28, < 0.34.29≥ 0.37.1, < 0.37.2 | 0.34.290.37.2 |
| cometbft | ≥ 0.34.28, < 0.34.29≥ 0.37.1, < 0.37.2 | 0.34.290.37.2 |
An internal modification 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:
consensus logging module to "debug" level (should not happen in production), anddump_consensus_stateCase 1 above, 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 after 2 minutes). The goroutines involved in the deadlock will not be garbage collected, but they will not interfere with the system after the peer is excluded.
The theoretical worst case for case 2, is a network with only two validator nodes. In this case, each of the nodes only has one struct. If is called in either node (or both), the chain will halt until the peer connections time out, after which the nodes will reconnect (with different structs) and the chain will progress again. Then, the same process can be repeated.
PeerStatedump_consensus_statePeerStateAs the number of nodes in a network increases, and thus, the number of peer struct each node maintains, the possibility of reproducing the perturbation visible with 2 nodes decreases. Only the first PeerState struct will deadlock, and not the others (RPC dump_consensus_state accesses them in a for loop, so the deadlock at the first iteration causes the rest of the iterations of that "for" loop to never be reached).
This regression was introduced in versions v0.34.28 and v0.37.1, and will be fixed in v0.34.29 and v0.37.2.
For case 1 (hitting the deadlock via logs)
For case 2 (hitting the deadlock via RPC dump_consensus_state)
dump_consensus_state RPC endpoint to the public internet (e.g., via rules in your nginx setup)Running one of these products? Scan your site to see whether it exposes a vulnerable version.
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