{"id":"PYSEC-2024-246","details":"Vyper is a pythonic Smart Contract Language for the Ethereum virtual machine. Starting in version 0.3.8 and prior to version 0.4.0b1, when looping over a `range` of the form `range(start, start + N)`, if `start` is negative, the execution will always revert. This issue is caused by an incorrect assertion inserted by the code generation of the range `stmt.parse_For_range()`. The issue arises when `start` is signed, instead of using `sle`, `le` is used and `start` is interpreted as an unsigned integer for the comparison. If it is a negative number, its 255th bit is set to `1` and is hence interpreted as a very large unsigned integer making the assertion always fail. Any contract having a `range(start, start + N)` where `start` is a signed integer with the possibility for `start` to be negative is affected. If a call goes through the loop while supplying a negative `start` the execution will revert. Version 0.4.0b1 fixes the issue.","aliases":["CVE-2024-32481","GHSA-ppx5-q359-pvwj"],"modified":"2026-06-10T17:14:16.630944247Z","published":"2024-04-25T17:15:50Z","references":[{"type":"ADVISORY","url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-ppx5-q359-pvwj"},{"type":"EVIDENCE","url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-ppx5-q359-pvwj"},{"type":"FIX","url":"https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868"},{"type":"FIX","url":"https://github.com/vyperlang/vyper/commit/5319cfbe14951e007ccdb323257e5ada869b35d5"},{"type":"WEB","url":"https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-ppx5-q359-pvwj"}],"affected":[{"package":{"name":"vyper","ecosystem":"PyPI","purl":"pkg:pypi/vyper"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.3.8"},{"fixed":"0.4.0b1"}]}],"versions":["0.3.10","0.3.10rc1","0.3.10rc2","0.3.10rc3","0.3.10rc4","0.3.10rc5","0.3.8","0.3.9"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/vyper/PYSEC-2024-246.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}