Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. In affected versions, the return of `<iface>.returns_int128()` is not validated to fall within the bounds of `int128`. This issue can result in a misinterpretation of the integer value and lead to incorrect behavior. As of v0.3.0, `<iface>.returns_int128()` is validated in simple expressions, but not complex expressions. Users are advised to upgrade. There is no known workaround for this issue.
Severity
CVSS 3.1
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
1.4% chance of exploitation in the next 30 days; higher than 72% of CVEs (scores of 2026-10-31)