GHSA-22qq-3xwm-r5x4 CometBFT allows a malicious peer to make node stuck in blocksync

• Go github.com/cometbft/cometbft: >= 1.0.0-alpha.1, < 1.0.1 → fixed in 1.0.1 • Go github.com/cometbft/cometbft: < 0.38.17 → fixed in 0.38.17

Name: ASA-2025-001: Malicious peer can disrupt node's ability to sync via blocksync Component: CometBFT [OUTDATED] Criticality: Medium (Considerable Impact; Possible Likelihood per ACMv1.2) Update of Criticality on 2026-03-06: We've made a mistake and over-rated the criticality of this bug in our initial triage. We have calibrated our vulnerability rating internally and updated the criticality of this bug to be Informational (Negligible Impact, Possible Likelihood) Affected versions: Y`. For example: ``` B: {base: 100, latest: 2000} B: {base: 100, latest: 1001} B: {base: 100, latest: 1002} ... ``` `A` will be trying to catch up to 2000 indefinitely. Even if `B` disconnects, the `latest` height (target height) won't be recalculated because `A` "doesn't know where 2000" came from per see. Impact Qualification This condition requires the introduction of malicious code in the full node first reporting a non-existing `latest` height, then reporting lower `latest` height and nodes which are syncing using `blocksync` protocol. Patches The new CometBFT releases v1.0.1 and v0.38.17 fix this issue. Unreleased code in the main is patched as well. Workarounds When the operator notices `blocksync` is stuck, they can identify the peer from which that message with "invalid" height was received. This may require increasing the logging level of the `blocksync` module. This peer can then be subsequently banned at the p2p layer as a temporary mitigation. References If you have questions about Interchain security efforts, please reach out to our official communication channel at [email protected]. For more information about the Interchain Foundation’s engagement with Amulet, and to sign up for security notification emails, please see https://github.com/interchainio/security. A Github Security Advisory for this issue is available in the CometBFT repository. For more information about CometBFT, see https://docs.cometbft.com/. EDIT: Please notice that this has been updated to be `informational` severity. This can be avoided by ensuring that one is not connected to a malicious peer during blocksync.