Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
Medium, CVSS 6.9

Babylon Incorrect FP inactive accounting in costaking creates “phantom stake” that earns rewards after BTC unbond

GHSA-4rmq-mc2c-r495

What to do

Partial vendor fix. Follow the primary source's mitigation guidance and check back for a fix.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

  • Go github.com/babylonlabs-io/babylon/v3

    Affected
    <= 3.0.0-snapshot.250805a
    Fixed in
    no fixed version recorded

  • Go github.com/babylonlabs-io/babylon/v4

    Affected
    < 4.2.0
    Fixed in
    4.2.0

  • Go github.com/babylonlabs-io/babylon/v2

    Affected
    <= 2.3.2
    Fixed in
    no fixed version recorded

  • Go github.com/babylonlabs-io/babylon

    Affected
    <= 1.1.0
    Fixed in
    no fixed version recorded

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N · score source
EPSS
No dated EPSS signal available.
Source description

As published by the source; long descriptions are shortened.

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 This creates a “phantom stake”: the delegator’s BTC capital is withdrawn, the FP is inactive, but costaking continues to treat the delegation as active BTC stake allowing ongoing rewards accrual without backing BTC.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.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-4rmq-mc2c-r495

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-4rmq-mc2c-r495

Advisory: Babylon Incorrect FP inactive accounting in costaking creates “phantom stake” that earns rewards after BTC unbond
IDs: GHSA-4rmq-mc2c-r495
Record: https://patchnext.com/advisories/ghsa-4rmq-mc2c-r495 (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: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: github.com/babylonlabs-io/babylon/v4 4.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/babylonlabs-io/babylon/v3: affected <= 3.0.0-snapshot.250805a
- Go github.com/babylonlabs-io/babylon/v4: affected < 4.2.0; fixed in 4.2.0
- Go github.com/babylonlabs-io/babylon/v2: affected <= 2.3.2
- Go github.com/babylonlabs-io/babylon: affected <= 1.1.0

## Suggested inspection (read-only)
- Go github.com/babylonlabs-io/babylon/v3: check the installed version with your package manager.
- Go github.com/babylonlabs-io/babylon/v4: check the installed version with your package manager.
- Go github.com/babylonlabs-io/babylon/v2: check the installed version with your package manager.
- Go github.com/babylonlabs-io/babylon: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/babylonlabs-io/babylon/v3, github.com/babylonlabs-io/babylon/v4, github.com/babylonlabs-io/babylon/v2, github.com/babylonlabs-io/babylon.
- 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-4rmq-mc2c-r495 (GitHub-reviewed advisory GHSA-4rmq-mc2c-r495 lists affected ranges: Go github.com/babylonlabs-io/babylon/v4 >=0 =0 =0 =0 <=1.1.0)

Commands are suggestions: review each one before running it.

Loading voting…