Vyper is a Pythonic smart contract language for the Ethereum virtual machine. Prior to version 0.3.8, internal calls with default arguments are compiled incorrectly. Depending on the number of arguments provided in the call, the defaults are added not right-to-left, but left-to-right. If the types are incompatible, typechecking is bypassed. The ability to pass kwargs to internal functions is an undocumented feature that is not well known about. The issue is patched in version 0.3.8.
https://github.com/vyperlang/vyper/security/advisories/GHSA-ph9x-4vc9-m39g
https://github.com/vyperlang/vyper/commit/c3e68c302aa6e1429946473769dd1232145822ac
Published: 2023-05-11
Updated: 2026-06-17
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:N
Severity: High
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: High
Base Score: 8.7
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00182