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."
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
| Link | Tags |
|---|---|
| https://twitter.com/AlexanderFisher/status/1060923428641878019 | third party advisory |
| https://github.com/ethereum/py-evm/issues/1448 | third party advisory exploit |
| https://twitter.com/NettaLab/status/1060889400102383617 | third party advisory |
| https://www.reddit.com/r/ethereum/comments/9vkk2g/netta_labs_claim_to_have_found_a_vulnerability_in/e9d3wyx/ | third party advisory |