{"id":"CVE-2024-32481","aliases":["GHSA-ppx5-q359-pvwj","PYSEC-2024-246"],"url":"https://o3.security/vulnerability/CVE-2024-32481","summary":"vyper's range(start, start + N) reverts for negative numbers","details":"### Summary\n\nWhen looping over a `range` of the form `range(start, start + N)`, if `start` is negative, the execution will always revert.\n \n### Details\n\nThis issue is caused by an incorrect assertion inserted by the code generation of the range (`stmt.parse_For_range()`):\n\nhttps://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287\n\nThis assertion was introduced in https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868 to fix https://github.com/advisories/GHSA-6r8q-pfpv-7cgj. 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. \n### PoC\n\n```Vyper\n@external\ndef foo():\n    x:int256 = min_value(int256)\n    # revert when it should not since we have the following assertion that fails:\n    # [assert, [le, min_value(int256), max_value(int256) + 1 - 10]],\n    for i in range(x, x + 10):\n        pass\n```\n\n### Patches\n\npatched in v0.4.0, specifically, https://github.com/vyperlang/vyper/pull/3679 disallows this form of `range()`.\n\n### Impact\n\nAny 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.","published":"2024-04-25T17:00:54.082Z","modified":"2026-10-28T02:31:08.471757574Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},"epss":{"score":0.00798,"percentile":0.53377,"asOf":"2026-08-23"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"vyper","fixedVersion":"0.4.0"}],"fix":{"url":"https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868","label":"vyperlang/vyper@3de1415"},"references":[{"type":"WEB","url":"https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/32xxx/CVE-2024-32481.json"},{"type":"ADVISORY","url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-ppx5-q359-pvwj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-32481"},{"type":"FIX","url":"https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868"},{"type":"FIX","url":"https://github.com/vyperlang/vyper/commit/5319cfbe14951e007ccdb323257e5ada869b35d5"},{"type":"PACKAGE","url":"https://github.com/vyperlang/vyper"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:31:08.471757574Z"}}