{"id":"CVE-2018-18920","details":"Py-EVM v0.2.0-alpha.33 allows attackers to make a vm.execute_bytecode call that triggers computation._stack.values with '\"stack\": [100, 100, 0]' where b'\\x' was expected, resulting in an execution failure because of an invalid opcode. This is reportedly related to \"smart contracts can be executed indefinitely without gas being paid.\"","aliases":["GHSA-vqgp-4jgj-5j64","PYSEC-2018-155","PYSEC-2018-96"],"modified":"2026-07-08T16:39:58.483523Z","published":"2018-11-12T02:29:00.233Z","references":[{"type":"ADVISORY","url":"https://twitter.com/AlexanderFisher/status/1060923428641878019"},{"type":"ADVISORY","url":"https://twitter.com/NettaLab/status/1060889400102383617"},{"type":"ADVISORY","url":"https://www.reddit.com/r/ethereum/comments/9vkk2g/netta_labs_claim_to_have_found_a_vulnerability_in/e9d3wyx/"},{"type":"EVIDENCE","url":"https://github.com/ethereum/py-evm/issues/1448"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ethereum/py-evm","events":[{"introduced":"a97dee05dba25cd743e5fc43c03add4dc5efd11c"},{"last_affected":"a97dee05dba25cd743e5fc43c03add4dc5efd11c"}],"database_specific":{"cpe":"cpe:2.3:a:ethereum:py-evm:0.2.0:alpha.33:*:*:*:*:*:*","extracted_events":[{"introduced":"0.2.0-alpha\\.33"},{"last_affected":"0.2.0-alpha\\.33"}],"source":"CPE_STRING"}}],"versions":["0.2.0-alpha\\.33","v0.2.0-alpha.33"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-18920.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}