Medium (5.3) in vyperlang vyper. EPSS 0.6% chance of exploitation in the next 30 days. Fixed in vyper 0.4.0.
Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. When using the built-in `extract32(b, start)`, if the `start` index provided has for side effect to update `b`, the byte array to extract `32` bytes from, it could be that some dirty memory is read and returned by `extract32`. This vulnerability is fixed in 0.4.0.
Severity
CVSS 3.1
5.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS
0.6% chance of exploitation in the next 30 days; higher than 46% of CVEs (scores of 2026-10-31)