PYSEC-2024-246

Vulnerability from pysec - Published: 2024-04-25 17:15 - Updated: 2025-05-05 19:21
VLAI
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.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Impacted products
Name purl
vyper pkg:pypi/vyper
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "vyper",
        "purl": "pkg:pypi/vyper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.3.8"
            },
            {
              "fixed": "0.4.0b1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "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"
      ]
    }
  ],
  "aliases": [
    "CVE-2024-32481",
    "GHSA-ppx5-q359-pvwj"
  ],
  "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.",
  "id": "PYSEC-2024-246",
  "modified": "2025-05-05T19:21:20.899426+00:00",
  "published": "2024-04-25T17:15:50+00:00",
  "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"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}



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