ghsa-69v6-xc2j-r2jf
Vulnerability from github
Published
2021-06-29 21:13
Modified
2025-01-30 14:37
Severity ?
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Summary
Shallow copy bug in geth
Details

Impact

This is a Consensus vulnerability, which can be used to cause a chain-split where vulnerable nodes reject the canonical chain.

Geth’s pre-compiled dataCopy (at 0x00...04) contract did a shallow copy on invocation. An attacker could deploy a contract that

  • writes X to an EVM memory region R,
  • calls 0x00..04 with R as an argument,
  • overwrites R to Y,
  • and finally invokes the RETURNDATACOPY opcode.

When this contract is invoked, a consensus-compliant node would push X on the EVM stack, whereas Geth would push Y.

Patches

No standalone patches have been made.

Workarounds

Upgrade to 1.9.17 or higher.

References

https://blog.ethereum.org/2020/11/12/geth_security_release/

For more information

If you have any questions or comments about this advisory: * Open an issue in go-ethereum * Email us at security@ethereum.org

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/ethereum/go-ethereum"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.9.7"
            },
            {
              "fixed": "1.9.17"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2020-26241"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-682"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-05-21T21:51:49Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\nThis is a Consensus vulnerability, which can be used to cause a chain-split where vulnerable nodes reject the canonical chain. \n\nGeth\u2019s pre-compiled `dataCopy` (at `0x00...04`) contract did a shallow copy on invocation. An attacker could deploy a contract that \n\n- writes `X` to an EVM memory region `R`,\n- calls `0x00..04` with `R` as an argument,\n- overwrites `R` to `Y`,\n- and finally invokes the `RETURNDATACOPY` opcode.\n\nWhen this contract is invoked, a consensus-compliant node would push `X` on the EVM stack, whereas Geth would push `Y`.\n\n\n### Patches\n\nNo standalone patches have been made. \n\n### Workarounds\n\nUpgrade to `1.9.17` or higher.\n\n### References\n\nhttps://blog.ethereum.org/2020/11/12/geth_security_release/\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [go-ethereum](https://github.com/ethereum/go-ethereum)\n* Email us at [security@ethereum.org](mailto:security@ethereum.org)\n",
  "id": "GHSA-69v6-xc2j-r2jf",
  "modified": "2025-01-30T14:37:49Z",
  "published": "2021-06-29T21:13:01Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-26241"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ethereum/go-ethereum/commit/295693759e5ded05fec0b2fb39359965b60da785"
    },
    {
      "type": "WEB",
      "url": "https://blog.ethereum.org/2020/11/12/geth_security_release"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ethereum/go-ethereum"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Shallow copy bug in geth"
}


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