CometBFT's invalid BitArray handling can lead to network halt

Exploitation

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

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Name: ASA-2025-003: Invalid BitArray handling can lead to network halt Criticality: High (Considerable Impact; Possible Likelihood per ACMv1.2) Affected versions: <= v0.38.18, <= v0.37.15, and main development branches Affected users: Validators, Full nodes, Users Description A bug was discovered in CometBFT's handling of BitArray's that have a mismatch between the BitArray's expected number of Elems for the specified number of Bits. Additional validation was added to prevent processing BitArray's in this invalid state, as well as guards to prevent panics on BitArray methods if one of these invalid states is processed. Impact BitArray's are present in a number of messages received from peers. When handling these messages, insufficient validation was applied to prevent processing messages the aforementioned invalid state. In the worst case, nodes will gossip messages to peers in an invalid state before processing them themselves, leading to a network halt (instead of only the node…

Published by the source

14 Oct 2025, 19:57 UTC

Last modified by the source

14 Oct 2025, 19:57 UTC

Source last checked

26 Oct 2026, 15:13 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-hrhf-2vcr-ghch

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# Patch Next advisory brief: GHSA-hrhf-2vcr-ghch

Advisory: CometBFT's invalid BitArray handling can lead to network halt
IDs: GHSA-hrhf-2vcr-ghch
Record: https://patchnext.com/advisories/ghsa-hrhf-2vcr-ghch (revision 1, source checked 26 Oct 2026, 15:13 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
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 0.38.19, 0.37.16. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/cometbft/cometbft: affected <= 0.37.15; >= 0.38.0-alpha.1, <= 0.38.18; fixed in 0.37.16, 0.38.19

## 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-hrhf-2vcr-ghch (GitHub-reviewed advisory GHSA-hrhf-2vcr-ghch lists affected ranges: Go github.com/cometbft/cometbft >=0 =0.38.0-alpha.1 <=0.38.18)

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