---
id: CVE-2021-41138
aliases:
  - GHSA-vj62-g63v-f8mf
title: Validity check missing in Frontier
summary: Validity check missing in Frontier
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'
vendor: pallet-ethereum
product: pallet-ethereum
ecosystem: rust
affected:
  - pallet-ethereum <= 3.0.0
published: '2021-10-13'
updated: '2026-07-08'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-vj62-g63v-f8mf'
references:
  - url: >-
      https://github.com/paritytech/frontier/security/advisories/GHSA-vj62-g63v-f8mf
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2021-41138'
  - url: 'https://github.com/paritytech/frontier/pull/495'
  - url: 'https://github.com/paritytech/frontier/pull/497'
  - url: >-
      https://github.com/paritytech/frontier/commit/146bb48849e5393004be5c88beefe76fdf009aba
  - url: 'https://github.com/polkadot-evm/frontier'
tags:
  - osv
  - rust
epss: 0.01383
epssPercentile: 0.71012
ingestedAt: '2026-07-09T18:56:37.332Z'
---

## Overview

### Impact

In the newly introduced signed Frontier-specific extrinsic for `pallet-ethereum`, a large part of transaction validation logic was only called in transaction pool validation, but not in block execution. Malicious validators can take advantage of this to put invalid transactions into a block.

The attack is limited in that the signature is always validated, and the majority of the validation is done again in the subsequent `pallet-evm` execution logic. However, do note that a chain ID replay attack was possible. In addition, spamming attacks are of main concerns, while they are limited by Substrate block size limits and other factors.

### Patches

The issue is patched in commit 146bb48849e5393004be5c88beefe76fdf009aba.

### References

Patch PR: https://github.com/paritytech/frontier/pull/495

### For more information

If you have any questions or comments about this advisory:
* Open an issue in [Frontier repo](https://github.com/paritytech/frontier/issues)

### Special thanks

Special thanks to @librelois, @nanocryk and the Moonbeam team for reporting and fixing this security vulnerability.

## Affected packages

- `pallet-ethereum <= 3.0.0`

## Remediation

Refer to the advisory for the patched release.