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GHSA-m6wq-66p2-c8pc

Babylon Nil BlockHash in BLS vote extensions triggers panics in consensus handlers

Also known asGO-2025-4211
Published
Dec 8, 2025
Updated
Dec 17, 2025
Affected
4 pkgs
Patched
1 / 4
Exploits
None indexed

Blast Radius

4 pkgs affected
🐹github.com/babylonlabs-io/babylon/v4🐹github.com/babylonlabs-io/babylon/v3🐹github.com/babylonlabs-io/babylon/v2🐹github.com/babylonlabs-io/babylon

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

A vulnerability exists in Babylon’s BLS vote extension processing where a malicious active validator can submit a VoteExtension with the block_hash field omitted from the protobuf serialization. Because protobuf fields are optional, unmarshalling succeeds but leaves BlockHash as nil. Babylon then dereferences this nil pointer in consensus-critical code paths (notably VerifyVoteExtension, and also proposal-time vote verification), causing a runtime panic.

Impact

Intermittent validator crashes at epoch boundaries, which would slow down the creation of the epoch boundary block.

Finder

Vulnerability discovered by:

  • @GrumpyLaurie55348

Affected Packages

4 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/babylonlabs-io/babylon/v4all versions4.2.0
🐹Gogithub.com/babylonlabs-io/babylon/v3all versionsNo fix
🐹Gogithub.com/babylonlabs-io/babylon/v2all versionsNo fix
🐹Gogithub.com/babylonlabs-io/babylonall versionsNo fix

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/babylonlabs-io/babylon/v4. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update github.com/babylonlabs-io/babylon/v4 to 4.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m6wq-66p2-c8pc is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-m6wq-66p2-c8pc is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-m6wq-66p2-c8pc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary A vulnerability exists in Babylon’s BLS vote extension processing where a malicious active validator can submit a VoteExtension with the `block_hash` field omitted from the protobuf serialization. Because protobuf fields are optional, unmarshalling succeeds but leaves `BlockHash` as nil. Babylon then dereferences this nil pointer in consensus-critical code paths (notably `VerifyVoteExtension`, and also proposal-time vote verification), causing a runtime panic. ### Impact Intermittent validator crashes at epoch boundaries, which would slow down the creation of the epoch boundary
O3 Security · Impact-Aware SCA

Is GHSA-m6wq-66p2-c8pc in your dependencies?

O3 detects GHSA-m6wq-66p2-c8pc across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.