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Medium

Security advisory

Type: advisorySources: OSVCVE: CVE-2021-41138

Frontier is Substrate's Ethereum compatibility layer. 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. The issue is patched in commit `146bb48849e5393004be5c88beefe76fdf009aba`.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2021-41138
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 11:55 UTC · Revision 1

Source evidence

CVE-2021-41138

core-osv · Original source

Published 13 Oct 2021, 16:15 UTC

Frontier is Substrate's Ethereum compatibility layer. 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. The issue is patched in commit `146bb48849e5393004be5c88beefe76fdf009aba`.

osv:CVE-2021-41138
Complete source record
{
  "id": "059f070f84a9b489dc8a40b49e5ce102676991be8f6fecc1975352e5c1bb9e88",
  "url": "https://osv.dev/vulnerability/CVE-2021-41138",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-41138",
    "summary": "Frontier is Substrate's Ethereum compatibility layer. 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. The issue is patched in commit `146bb48849e5393004be5c88beefe76fdf009aba`.",
    "evidence": "osv:CVE-2021-41138",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-41138",
      "aliases": [
        "CVE-2021-41138",
        "GHSA-vj62-g63v-f8mf"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/polkadot-evm/frontier",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "146bb48849e5393004be5c88beefe76fdf009aba"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "fixed": "146bb48849e5393004be5c88beefe76fdf009aba"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "pallet-evm-v5.0.0",
            "pallet-ethereum-v3.0.0",
            "pallet-dynamic-fee-v3.0.0",
            "fp-storage-v2.0.0",
            "fc-consensus-v2.0.0",
            "pallet-dynamic-fee-v2.0.0",
            "pallet-ethereum-v2.0.0",
            "fp-rpc-v2.1.0",
            "pallet-evm-v4.0.0",
            "fp-storage-v1.0.1",
            "fp-rpc-v2.0.0",
            "fp-evm-v2.0.0",
            "pallet-evm-v3.0.0",
            "pallet-evm-precompile-simple-v1.0.0",
            "pallet-evm-precompile-sha3fips-v1.0.0",
            "pallet-evm-precompile-modexp-v1.0.0",
            "pallet-evm-precompile-ed25519-v1.0.0",
            "pallet-evm-precompile-dispatch-v1.0.0",
            "pallet-evm-precompile-bn128-v1.0.0",
            "pallet-evm-precompile-blake2-v1.0.0",
            "pallet-ethereum-v1.0.0",
            "pallet-dynamic-fee-v1.0.0",
            "fp-storage-v1.0.0",
            "fp-rpc-v1.0.0",
            "fp-evm-v1.0.0",
            "fp-consensus-v1.0.0",
            "fc-rpc-v1.0.0",
            "fc-rpc-core-v1.0.0",
            "fc-mapping-sync-v1.0.0",
            "fc-db-v1.0.0",
            "fc-consensus-v1.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-41138.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:57.560370543Z",
      "provider": "osv",
      "references": [
        "https://github.com/paritytech/frontier/commit/146bb48849e5393004be5c88beefe76fdf009aba",
        "https://github.com/paritytech/frontier/pull/497",
        "https://github.com/paritytech/frontier/security/advisories/GHSA-vj62-g63v-f8mf"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:a:parity:frontier:*:*:*:*:*:*:*:*"
            ],
            "vendor_product": "parity:frontier",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "2021-09-30"
                  },
                  {
                    "fixed": "2021-10-13"
                  }
                ],
                "source": "CPE_RANGE"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-41138",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 386543,
  "published_at": "2021-10-13T16:15:07.847+00:00"
}