CometBFT PeerState JSON serialization deadlock

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2023-34450: 0.85% estimated exploitation activity in the next 30 days; percentile 58.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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: 1. Via logs Setting the consensus logging module to "debug" level (should not happen in production), and Setting the log output format to JSON 2. Via RPC dumpconsensusstate Case 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…

Published by the source

5 Jul 2023, 21:33 UTC

Last modified by the source

5 Nov 2023, 05:04 UTC

Source last checked

26 Oct 2026, 14:59 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-mvj3-qrqh-cjvr

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# Patch Next advisory brief: CVE-2023-34450

Advisory: CometBFT PeerState JSON serialization deadlock
IDs: CVE-2023-34450, GHSA-mvj3-qrqh-cjvr
Record: https://patchnext.com/advisories/cve-2023-34450 (revision 1, source checked 26 Oct 2026, 14:59 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/cometbft/cometbft 0.37.2, 0.34.29. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/cometbft/cometbft: affected >= 0.34.28, <= 0.34.28; >= 0.37.1, <= 0.37.1; fixed in 0.34.29, 0.37.2

## Suggested inspection (read-only)
- Go github.com/cometbft/cometbft: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/cometbft/cometbft.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-mvj3-qrqh-cjvr (GitHub-reviewed advisory GHSA-mvj3-qrqh-cjvr lists affected ranges: Go github.com/cometbft/cometbft >=0.34.28 =0.37.1 <=0.37.1)

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