{"id":"CVE-2018-20421","details":"Go Ethereum (aka geth) 1.8.19 allows attackers to cause a denial of service (memory consumption) by rewriting the length of a dynamic array in memory, and then writing data to a single memory location with a large index number, as demonstrated by use of \"assembly { mstore }\" followed by a \"c[0xC800000] = 0xFF\" assignment.","modified":"2026-08-07T14:49:49.969995Z","published":"2018-12-24T03:29:00.353Z","references":[{"type":"EVIDENCE","url":"https://github.com/ethereum/go-ethereum/issues/18289"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ethereum/go-ethereum","events":[{"introduced":"dae82f098570e15d44584f0d7f350713f4774727"},{"last_affected":"dae82f098570e15d44584f0d7f350713f4774727"}],"database_specific":{"source":"CPE_STRING","cpe":"cpe:2.3:a:ethereum:go_ethereum:1.8.19:*:*:*:*:*:*:*","extracted_events":[{"introduced":"1.8.19"},{"last_affected":"1.8.19"}]}}],"versions":["1.8.19","v1.8.19"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-20421.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}