{"cve":"CVE-2020-26241","nvd":{"published":"2020-11-25T02:15:11.047","modified":"2026-06-17T03:07:54.053","status":"Modified","description":"Go Ethereum, or \"Geth\", is the official Golang implementation of the Ethereum protocol. This is a Consensus vulnerability in Geth before version 1.9.17 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, then calls 0x00..04 with R as an argument, then 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. This is fixed in version 1.9.17.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L","score":7.1},"cwes":["CWE-682"],"references":["https://blog.ethereum.org/2020/11/12/geth_security_release/","https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf","https://blog.ethereum.org/2020/11/12/geth_security_release/","https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf"],"products":["ethereum:go_ethereum"],"source":"nvd","synced_at":"2026-10-19T21:11:20.317016139+00:00"},"epss":{"cve":"CVE-2020-26241","score":0.01226,"percentile":0.68847,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-69v6-xc2j-r2jf","url":"https://osv.dev/vulnerability/GHSA-69v6-xc2j-r2jf","summary":"Shallow copy bug in geth","modified":"2026-07-08T06:00:35.934223631Z","packages":[{"ecosystem":"Go","name":"github.com/ethereum/go-ethereum","purl":"pkg:golang/github.com/ethereum/go-ethereum","ranges":[">=1.9.7 <1.9.17"],"fixed":["1.9.17"]}]},{"id":"GO-2022-0771","url":"https://osv.dev/vulnerability/GO-2022-0771","summary":"Shallow copy bug in geth in github.com/ethereum/go-ethereum","modified":"2026-03-03T04:50:50.860337Z","packages":[{"ecosystem":"Go","name":"github.com/ethereum/go-ethereum","purl":"pkg:golang/github.com/ethereum/go-ethereum","ranges":[">=1.9.7 <1.9.17"],"fixed":["1.9.17"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}