CVE-2023-34450: CometBFT is a Byzantine Fault Tolerant (BFT) middleware that takes a state transition machine and replicates i

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LOW 3.7REMOTEUPGRADE

CVE-2023-34450 is a low-severity flaw (CVSS 3.7) affecting cometbft. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	3.7 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 42%)
CISA exploited list	No
Weakness	CWE-401, CWE-770
Published	2023-07-03
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: cometbft

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-07-03 17:15 UTCPublished CVE record published
2026-06-17 06:03 UTCUpdated Record last modified

cometbft cometbft UPGRADE

Affected: >= 0.34.28 and < 0.34.29 · >= 0.37.1 and < 0.37.2

Fixed in: 0.34.29, 0.37.2

Safe to downgrade to: a release before 0.34.28

1. Check installed version

apt-cache policy cometbft || rpm -q cometbft || cometbft --version

2. UPGRADE to 0.34.29 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade cometbft

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cometbft

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.34.28 (Debian / Ubuntu)

apt-cache madison cometbft sudo apt install cometbft=<VERSION_BEFORE_0.34.28> sudo apt-mark hold cometbft

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list cometbft sudo dnf downgrade cometbft-<VERSION_BEFORE_0.34.28> sudo dnf versionlock add cometbft

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-34450?

cometbft: upgrade to 0.34.29, 0.37.2. Exact commands for each OS are on this page.

Is CVE-2023-34450 being exploited?

CVE-2023-34450 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-34450 affect?

CVE-2023-34450 affects cometbft. Severity is low (CVSS 3.7). 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 JS

How urgent is CVE-2023-34450?

Priority 37/100. Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2023-34451 HIGH 8.2 UPGRADE CometBFT is a Byzantine Fault Tolerant (BFT) middleware that takes a state transition machine and replicates i

References

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