CVE-2018-18920: Ethereum Py-Evm

High severity, CVSS 8.8. EPSS: 2.9% chance of exploitation in the next 30 days.

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."

Affected products

• Ethereum Py-Evm: version 0.2.0 only

Published 2018-11-12. Last modified 2026-06-17.