CVE-2023-34450
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedCometBFT 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 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 `PeerState` struct. If `dump_consensus_state` 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 `PeerState` structs) and the chain will progress again. Then, the same process can be repeated. As 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 two 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 fixed in versions 0.34.29 and 0.37.2. Some workarounds are available. For case 1 (hitting the deadlock via logs), either don't set the log output to "json", leave at "plain", or don't set the consensus logging module to "debug", leave it at "info" or higher. For case 2 (hitting the deadlock via RPC `dump_consensus_state`), do not expose `dump_consensus_state` RPC endpoint to the public internet (e.g., via rules in one's nginx setup).
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisAllocated memory is never released on some path, so a long-running service or a repeatedly triggered request steadily consumes memory until performance degrades or the process crashes. Attackers exploit it by simply driving the leaking path. Remediation is pairing every allocation with a release and using ownership patterns or tooling to catch what leaks.
General guidance for the memory leak class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 0.34.28, < 0.34.29>= 0.37.1, < 0.37.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped0.34.290.37.2
Upgrade to CometBFT v0.34.29 (if on 0.34.x) or v0.37.2 (if on 0.37.x)
- 1. Identify the current CometBFT version in use by checking the go.mod file or running `cometbft version`
- 2. If running version 0.34.x (>= 0.34.28), upgrade to version 0.34.29
- 3. If running version 0.37.x (>= 0.37.1), upgrade to version 0.37.2
- 4. Update the dependency in go.mod: `go get github.com/cometbft/[email protected]` or `go get github.com/cometbft/[email protected]`
- 5. Run `go mod tidy` to update dependencies
- 6. Rebuild and redeploy the CometBFT node
- 7. Verify the node is running the fixed version with `cometbft version`
- 8. As an interim mitigation before upgrading, ensure the consensus logging module is set to 'info' or higher (not 'debug') and log format is 'plain' (not 'json') if using debug logging; also restrict access to the `dump_consensus_state` RPC endpoint to prevent external access
Generated from the published advisory — verify against the referenced sources before acting.
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Free · runs locallyCheck whether your project pulls in CVE-2023-34450 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-34450 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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