GHSA-4rmq-mc2c-r495
Babylon Incorrect FP inactive accounting in costaking creates “phantom stake” that earns rewards after BTC unbond
Blast Radius
github.com/babylonlabs-io/babylon/v4🐹github.com/babylonlabs-io/babylon/v3🐹github.com/babylonlabs-io/babylon/v2🐹github.com/babylonlabs-io/babylonReal-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 state consistency bug in x/costaking can leave a BTC delegator with non-zero ActiveSatoshis (Phatom Stake) even after they have fully unbonded their BTC delegation, if their Finality Provider (FP) drops out of the active set in the exact same babylon block height. This creates a “phantom stake”: the delegator’s BTC capital is withdrawn, the FP is inactive, but costaking continues to treat the delegation as active BTC stake allowing ongoing rewards accrual without backing BTC.
Impact
An address can keep earning costaking rewards with zero BTC staked.
Reported by @BottyBott.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/babylonlabs-io/babylon/v4 | all versions | 4.2.0 |
| 🐹Go | github.com/babylonlabs-io/babylon/v3 | all versions | No fix |
| 🐹Go | github.com/babylonlabs-io/babylon/v2 | all versions | No fix |
| 🐹Go | github.com/babylonlabs-io/babylon | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
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.
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-4rmq-mc2c-r495 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 pinpoints whether GHSA-4rmq-mc2c-r495 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-4rmq-mc2c-r495. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-4rmq-mc2c-r495 in your dependencies?
O3 detects GHSA-4rmq-mc2c-r495 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.