{"id":"CVE-2020-26241","state":"PUBLISHED","title":"Shallow copy bug in geth","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.","publishedAt":"2020-11-25T01:25:20.000Z","updatedAt":"2024-08-04T15:56:03.871Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["ethereum go-ethereum"],"affected":[{"vendor":"ethereum","product":"go-ethereum","versions":[{"version":">= 1.9.7, < 1.9.17","status":"affected"}]}],"references":["https://blog.ethereum.org/2020/11/12/geth_security_release/","https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf"],"weaknesses":["CWE-682"],"ingestedAt":"2026-10-29T19:47:08.370Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2020/26xxx/CVE-2020-26241.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2020-26241","state":"PUBLISHED","datePublished":"2020-11-25T01:25:20.000Z","dateUpdated":"2024-08-04T15:56:03.871Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2020-10-01T00:00:00.000Z"},"containers":{"cna":{"title":"Shallow copy bug in geth","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"ethereum","product":"go-ethereum","versions":[{"version":">= 1.9.7, < 1.9.17","status":"affected"}]}],"references":[{"url":"https://blog.ethereum.org/2020/11/12/geth_security_release/","tags":["x_refsource_MISC"]},{"url":"https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-682","description":"CWE-682: Incorrect Calculation","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","dateUpdated":"2020-11-25T01:25:20.000Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa"},"source":{"advisory":"GHSA-69v6-xc2j-r2jf","discovery":"UNKNOWN"},"x_legacyV4Record":{"CVE_data_meta":{"ASSIGNER":"security-advisories@github.com","ID":"CVE-2020-26241","STATE":"PUBLIC","TITLE":"Shallow copy bug in geth"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"go-ethereum","version":{"version_data":[{"version_value":">= 1.9.7, < 1.9.17"}]}}]},"vendor_name":"ethereum"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"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."}]},"impact":{"cvss":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-682: Incorrect Calculation"}]}]},"references":{"reference_data":[{"name":"https://blog.ethereum.org/2020/11/12/geth_security_release/","refsource":"MISC","url":"https://blog.ethereum.org/2020/11/12/geth_security_release/"},{"name":"https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf","refsource":"CONFIRM","url":"https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf"}]},"source":{"advisory":"GHSA-69v6-xc2j-r2jf","discovery":"UNKNOWN"}}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://blog.ethereum.org/2020/11/12/geth_security_release/","tags":["x_refsource_MISC","x_transferred"]},{"url":"https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf","tags":["x_refsource_CONFIRM","x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-04T15:56:03.871Z"}}]}}}