CVE-2020-26241: Github.com/ethereum/go ethereum Shallow Copy Bug Vulnerability

Q: What is CVE-2020-26241?

CVE-2020-26241 is a security vulnerability in Github.com/ethereum/go ethereum involving Shallow copy bug in geth under CWE-682: Incorrect Calculation.

Q: Which Github.com/ethereum/go ethereum versions are affected?

Affected versions include releases prior to 1.9.17 across affected packages: github.com/ethereum/go-ethereum.

Q: What version fixes CVE-2020-26241?

Upgrading to 1.9.17 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is github.com/ethereum/go-ethereum affected?

Yes, github.com/ethereum/go-ethereum is affected in releases prior to 1.9.17. Upgrade your dependency to 1.9.17 or later.

Q: What is the CVSS score of CVE-2020-26241?

CVE-2020-26241 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.

Q: What CWE is associated with CVE-2020-26241?

CVE-2020-26241 is classified under CWE-682: Incorrect Calculation (The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.).

Q: How can I check Go dependencies for CVE-2020-26241?

Run the dependency tree command: 'inspect dependencies for github.com/ethereum/go-ethereum'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

MODERATE

Advisory Identifier: GHSA-69v6-xc2j-r2jf

CVSS 6.5

CWE-682

Published 2021-06-29

Advisory Summary

CVE-2020-26241 is a MODERATE (CVSS 6.5) shallow copy bug vulnerability (CWE-682: Incorrect Calculation) affecting Github.com/ethereum/go ethereum libraries in the Go ecosystem. The issue involves shallow copy bug in geth. Remediation is available by upgrading affected packages to version 1.9.17.

CVE-2020-26241 at a Glance

CVE Identifier CVE-2020-26241

GHSA Identifier GHSA-69v6-xc2j-r2jf

Severity MODERATE

CVSS v3.1 Base Score 6.5

CWE Classification CWE-682: Incorrect Calculation

Affected Product Github.com/ethereum/go ethereum

Package Ecosystem Go

Published Date 2021-06-29

Last Updated 2025-01-30

Security Impact

CVSS: 6.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)

Attack Complexity Low (AC:L)

Privileges Required Low (PR:L)

User Interaction None (UI:N)

Scope Unchanged (S:U)

Confidentiality None (C:N)

Integrity High (I:H)

Availability None (A:N)

How to Fix CVE-2020-26241

To remediate this vulnerability, upgrade all affected Github.com/ethereum/go ethereum dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/ethereum/go-ethereum fixed: 1.9.17

Upgrade github.com/ethereum/go-ethereum to 1.9.17

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for github.com/ethereum/go-ethereum

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-26241, inspect your project dependencies for Github.com/ethereum/go ethereum:

inspect dependencies for github.com/ethereum/go-ethereum

Analyze the terminal output to locate any version of Github.com/ethereum/go ethereum in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.9.17), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-682: Incorrect Calculation, where the product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management. In Github.com/ethereum/go ethereum, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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](https://github.com/ethereum/go-ethereum) * Email us at [security@ethereum.org](mailto:security@ethereum.org)

CVE-2020-26241 Affected Github.com/ethereum/go ethereum Versions

1 component(s)

Fixed Versions:

1.9.17

Product / Package	Ecosystem	Affected Versions	Fixed Version
github.com/ethereum/go-ethereum golang/github.com/ethereum/go-ethereum	Go	≥ 1.9.7 < 1.9.17	1.9.17

References

GitHub Advisory / Wiki ADVISORY

https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf

NVD — CVE-2020-26241 NVD

https://nvd.nist.gov/vuln/detail/CVE-2020-26241

Security Fix Commit FIX COMMIT

https://github.com/ethereum/go-ethereum/commit/295693759e5ded05fec0b2fb39359965b60da785

Github.com/ethereum/go ethereum Release RELEASE

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

Github.com/ethereum/go ethereum Source Repository REPOSITORY

https://github.com/ethereum/go-ethereum

Frequently Asked Questions

What is CVE-2020-26241?

CVE-2020-26241 is a security vulnerability in Github.com/ethereum/go ethereum involving Shallow copy bug in geth under CWE-682: Incorrect Calculation.

Which Github.com/ethereum/go ethereum versions are affected?

Affected versions include releases prior to 1.9.17 across affected packages: github.com/ethereum/go-ethereum.

What version fixes CVE-2020-26241?

Upgrading to 1.9.17 (or the latest patched release for your respective branch) resolves the vulnerability.

Is github.com/ethereum/go-ethereum affected?

Yes, github.com/ethereum/go-ethereum is affected in releases prior to 1.9.17. Upgrade your dependency to 1.9.17 or later.

What is the CVSS score of CVE-2020-26241?

CVE-2020-26241 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.

What CWE is associated with CVE-2020-26241?

CVE-2020-26241 is classified under CWE-682: Incorrect Calculation (The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.).

How can I check Go dependencies for CVE-2020-26241?

Run the dependency tree command: 'inspect dependencies for github.com/ethereum/go-ethereum'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

Machine-readable OSV JSON OSV v1.5 Schema

Normalized schema output

View Raw JSON

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-69v6-xc2j-r2jf",
  "modified" : "2025-01-30T14:37:49Z",
  "published" : "2021-06-29T21:13:01Z",
  "aliases" : [ "CVE-2020-26241" ],
  "summary" : "Shallow copy bug in geth",
  "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’s 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",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/ethereum/go-ethereum"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.9.7"
      }, {
        "fixed" : "1.9.17"
      } ]
    } ]
  } ],
  "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-682" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-21T21:51:49Z",
    "nvd_published_at" : null
  }
}

CVSS V3

6.5 MODERATE