{"id":"CVE-2020-26265","aliases":["GHSA-xw37-57qp-9mm4","GO-2021-0105"],"url":"https://o3.security/vulnerability/CVE-2020-26265","summary":"Consensus flaw during block processing in github.com/ethereum/go-ethereum","details":"Go Ethereum, or \"Geth\", is the official Golang implementation of the Ethereum protocol. In Geth from version 1.9.4 and before version 1.9.20 a consensus-vulnerability could cause a chain split, where vulnerable versions refuse to accept the canonical chain. The fix was included in the Paragade release version 1.9.20. No individual workaround patches have been made -- all users are recommended to upgrade to a newer version.","published":"2020-12-11T17:15:12.870Z","modified":"2026-08-07T15:12:16.707352Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Go","name":"github.com/ethereum/go-ethereum","fixedVersion":"1.9.20"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/ethereum/go-ethereum/releases/tag/v1.9.20"},{"type":"ADVISORY","url":"https://github.com/ethereum/go-ethereum/security/advisories/GHSA-xw37-57qp-9mm4"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T15:12:16.707352Z"}}