{"schema_version":"1.7.5","id":"GHSA-69v6-xc2j-r2jf","published":"2021-06-29T21:13:01Z","modified":"2026-07-08T06:00:35.934223631Z","aliases":["CVE-2020-26241","GO-2022-0771"],"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","affected":[{"package":{"name":"github.com/ethereum/go-ethereum","ecosystem":"Go","purl":"pkg:golang/github.com/ethereum/go-ethereum"},"ranges":[{"type":"SEMVER","events":[{"introduced":"1.9.7"},{"fixed":"1.9.17"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/06/GHSA-69v6-xc2j-r2jf/GHSA-69v6-xc2j-r2jf.json"}}],"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"],"github_reviewed":true,"github_reviewed_at":"2021-05-21T21:51:49Z","nvd_published_at":null,"severity":"MODERATE"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"}]}