---
id: CVE-2021-39193
aliases:
  - GHSA-hw4v-5x4h-c3xm
title: Transaction validity oversight in pallet-ethereum
summary: Transaction validity oversight in pallet-ethereum
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: '2021-09-01'
updated: '2026-07-08'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-hw4v-5x4h-c3xm'
references:
  - url: >-
      https://github.com/paritytech/frontier/security/advisories/GHSA-hw4v-5x4h-c3xm
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2021-39193'
  - url: 'https://github.com/paritytech/frontier/pull/465'
  - url: >-
      https://github.com/paritytech/frontier/pull/465/commits/8a2b890a2fb477d5fedd0e4335b00623832849ae
  - url: >-
      https://github.com/paritytech/frontier/commit/0b962f218f0cdd796dadfe26c3f09e68f7861b26
  - url: 'https://github.com/paritytech/frontier/commit/dd112e'
  - url: 'https://github.com/polkadot-evm/frontier'
tags:
  - osv
  - rust
epss: 0.01189
epssPercentile: 0.66602
ingestedAt: '2026-07-09T18:56:37.313Z'
---

## Overview

### Impact

A bug in `pallet-ethereum` can cause invalid transactions to be included in the Ethereum block state in `pallet-ethereum` due to not validating the input data size. Any invalid transactions included this way have no possibility to alter the internal Ethereum or Substrate state. The transaction will appear to have be included, but is of no effect as it is rejected by the EVM engine. The impact is further limited by Substrate extrinsic size constraints.

### Patches

Patches are applied in PR #465.

### Workarounds

None.

### References

Patch PR: https://github.com/paritytech/frontier/pull/465

### For more information

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


## Affected packages

- `pallet-ethereum <= 3.0.0`

## Remediation

Refer to the advisory for the patched release.