How severe is GHSA-4rmq-mc2c-r495?

No CVSS score has been assigned to GHSA-4rmq-mc2c-r495 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-4rmq-mc2c-r495?

GHSA-4rmq-mc2c-r495 affects the following packages: github.com/babylonlabs-io/babylon/v4 (Go), github.com/babylonlabs-io/babylon/v3 (Go), github.com/babylonlabs-io/babylon/v2 (Go), github.com/babylonlabs-io/babylon (Go). Ecosystems affected: Go.

How do I fix GHSA-4rmq-mc2c-r495?

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.

How do I detect GHSA-4rmq-mc2c-r495 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/babylonlabs-io/babylon/v4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-4rmq-mc2c-r495 if there is no patch (or I can't update yet)?

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.

Is GHSA-4rmq-mc2c-r495 actively exploited in the wild?

No public exploit code has been indexed for GHSA-4rmq-mc2c-r495 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-4rmq-mc2c-r495 published, and has it been updated?

GHSA-4rmq-mc2c-r495 was published on December 9, 2025 and was last updated on December 15, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

Babylon Incorrect FP inactive accounting in costaking creates “phantom stake” that earns rewards after BTC unbondGHSA-4rmq-mc2c-r495

Fix: babylonlabs-io/babylon@e65c3a5

GHSA-4rmq-mc2c-r495 is a security vulnerability in github.com/babylonlabs-io/babylon/v4. A fix is available for github.com/babylonlabs-io/babylon/v4 — see the affected versions and patch details below.

Also known asGO-2025-4214

Published

Dec 9, 2025

Updated

Dec 15, 2025

Affected

4 pkgs

Patched

1 / 4

Exploits

None indexed

Exploitation data as of Dec 15, 2025 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

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 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

4 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/babylonlabs-io/babylon/v4`	all versions	4.2.0`go get github.com/babylonlabs-io/babylon/v4@v4.2.0`
🐹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 dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/babylonlabs-io/babylon/v4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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.

Frequently Asked Questions

### 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 @Botty

O3 Security · Impact-Aware SCA

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