CVE-2025-24371 Malicious peer can make node stuck in blocksync in github.com/cometbft/cometbft
A malicious peer can cause a syncing node to hang indefinitely by reporting inconsistent block heights, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-24371?
CVE-2025-24371 is a high-severity denial of service vulnerability in cometbft, published on 3 Feb 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-703
Which versions are affected by CVE-2025-24371?
6 open source packages ship an affected version, including github.com/cometbft/cometbft.
| Package | Affected | Fixed in |
|---|---|---|
github.com/cometbft/cometbft Go | All versions | 0.38.17 |
github.com/cometbft/cometbft Go | All versions | 0.38.17 |
github.com/cometbft/cometbft Go | All versions | 0.38.17 |
github.com/cometbft/cometbft Go | All versions | 1.0.1 |
github.com/cometbft/cometbft Go | From 1.0.0-alpha.1 | 1.0.1 |
github.com/cometbft/cometbft Go | From 1.0.0-alpha.1 | 1.0.1 |
How do I fix CVE-2025-24371?
Upgrade github.com/cometbft/cometbft to a fixed version for your release line: 0.38.17 or 1.0.1.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-24371 being exploited?
There is no known exploitation of CVE-2025-24371 in the wild and no public exploit code.
Sources
Also known as GHSA-22qq-3xwm-r5x4, GO-2025-3442.