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High, CVSS 7.5

Drainage of FeeCollector's Block Transaction Fees in cronos

CVE-2021-43839GHSA-f854-hpxv-cw9r

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.

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Affected packages

  • Go github.com/tharsis/evmos

    Affected
    <= 0.4.2
    Fixed in
    no fixed version recorded

  • Go github.com/tharsis/ethermint

    Affected
    >= 0.8.0, < 0.10.0< 0.7.3
    Fixed in
    0.7.3, 0.10.0

  • Go github.com/crypto-org-chain/cronos

    Affected
    < 0.6.5
    Fixed in
    0.6.5

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS
  • CVE-2021-43839: 1.36% estimated exploitation activity in the next 30 days; percentile 71.67 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Impact In Cronos nodes running versions before v0.6.5, it is possible to take transaction fees from Cosmos SDK's FeeCollector for the current block by sending a custom crafted MsgEthereumTx. User funds and balances are safe. Patches This problem has been patched in Cronos v0.6.5 on the mempool level. The next network upgrade with consensus-breaking changes will patch it on the consensus level. Workarounds There are no tested workarounds. All validator node operators are recommended to upgrade to Cronos v0.6.5 at their earliest possible convenience. Credits Thank you to @zb3 for reporting this issue on Cronos Immunefi Bug Bounty Program, to @cyril-crypto for reproducing the issue and to @yihuang and @thomas-nguy for patching the issue on the CheckTx (mempool) and the DeliverTx (consensus) levels. For more information If you have any questions or comments about this advisory: Open a discussion in crypto-org-chain/cronos Email us at chain@crypto.org

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

    Published from ghsa record GHSA-f854-hpxv-cw9r

Agent brief

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

# Patch Next advisory brief: CVE-2021-43839

Advisory: Drainage of FeeCollector's Block Transaction Fees in cronos
IDs: CVE-2021-43839, GHSA-f854-hpxv-cw9r
Record: https://patchnext.com/advisories/cve-2021-43839 (revision 1, source checked 26 Oct 2026, 14:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: github.com/tharsis/ethermint 0.10.0, 0.7.3; github.com/crypto-org-chain/cronos 0.6.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/tharsis/evmos: affected <= 0.4.2
- Go github.com/tharsis/ethermint: affected >= 0.8.0, < 0.10.0; < 0.7.3; fixed in 0.7.3, 0.10.0
- Go github.com/crypto-org-chain/cronos: affected < 0.6.5; fixed in 0.6.5

## Suggested inspection (read-only)
- Go github.com/tharsis/evmos: check the installed version with your package manager.
- Go github.com/tharsis/ethermint: check the installed version with your package manager.
- Go github.com/crypto-org-chain/cronos: 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/tharsis/evmos, github.com/tharsis/ethermint, github.com/crypto-org-chain/cronos.
- 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-f854-hpxv-cw9r (GitHub-reviewed advisory GHSA-f854-hpxv-cw9r lists affected ranges: Go github.com/crypto-org-chain/cronos >=0 =0.8.0 =0 =0 <=0.4.2)

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