CVE-2025-24371

CVE-2025-24371 is a high-severity vulnerability with a CVSS 4.0 base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-703.

Key facts

Description

CometBFT is a distributed, Byzantine fault-tolerant, deterministic state machine replication engine. In the `blocksync` protocol peers send their `base` and `latest` heights when they connect to a new node (`A`), which is syncing to the tip of a network. `base` acts as a lower ground and informs `A` that the peer only has blocks starting from height `base`. `latest` height informs `A` about the latest block in a network. Normally, nodes would only report increasing heights. If `B` fails to provide the latest block, `B` is removed and the `latest` height (target height) is recalculated based on other nodes `latest` heights. The existing code however doesn't check for the case where `B` first reports `latest` height `X` and immediately after height `Y`, where `X > Y`. `A` will be trying to catch up to 2000 indefinitely. This condition requires the introduction of malicious code in the full node first reporting some non-existing `latest` height, then reporting lower `latest` height and nodes which are syncing using `blocksync` protocol. This issue has been patched in versions 1.0.1 and 0.38.17 and all users are advised to upgrade. Operators may attempt to ban malicious peers from the network as a workaround.

Frequently asked questions

What is CVE-2025-24371?
CometBFT is a distributed, Byzantine fault-tolerant, deterministic state machine replication engine. In the `blocksync` protocol peers send their `base` and `latest` heights when they connect to a new node (`A`), which is syncing to the tip of a network. `base` acts as a lower ground and informs `A` that the peer only has blocks starting from height `base`. `latest` height informs `A` about the latest block in a network. Normally, nodes would only report increasing heights. If `B` fails to provide the latest block, `B` is removed and the `latest` height (target height) is recalculated based on other nodes `latest` heights. The existing code however doesn't check for the case where `B` first reports `latest` height `X` and immediately after height `Y`, where `X > Y`. `A` will be trying to catch up to 2000 indefinitely. This condition requires the introduction of malicious code in the full node first reporting some non-existing `latest` height, then reporting lower `latest` height and nodes which are syncing using `blocksync` protocol. This issue has been patched in versions 1.0.1 and 0.38.17 and all users are advised to upgrade. Operators may attempt to ban malicious peers from the network as a workaround.
How severe is CVE-2025-24371?
CVE-2025-24371 has a CVSS 4.0 base score of 7.1, rated high severity.
Is CVE-2025-24371 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-24371?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-24371 have an EU (EUVD) identifier?
Yes. CVE-2025-24371 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-0216.
When was CVE-2025-24371 published?
CVE-2025-24371 was published on 2025-02-03 and last updated on 2026-06-17.

References

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