GHSA-CX2Q-HFXR-RJ97

Vulnerability from github – Published: 2023-09-26 19:34 – Updated: 2024-11-19 17:23
VLAI?
Summary
Vyper's `_abi_decode` input not validated in complex expressions
Details

Impact

_abi_decode() does not validate input when it is nested in an expression. the following example gets correctly validated (bounds checked):

x: int128 = _abi_decode(slice(msg.data, 4, 32), int128)

however, the following example is not bounds checked

@external
def abi_decode(x: uint256) -> uint256:
    a: uint256 = convert(_abi_decode(slice(msg.data, 4, 32), (uint8)), uint256) + 1
    return a  # abi_decode(256) returns: 257

the issue can be triggered by constructing an example where the output of _abi_decode is not internally passed to make_setter (an internal codegen routine) or other input validating routine.

Patches

https://github.com/vyperlang/vyper/pull/3626

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

References

Are there any links users can visit to find out more?

Severity ?
5.3 (Medium)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
6.0 (Medium)
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "vyper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.3.4"
            },
            {
              "fixed": "0.3.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-42460"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-682"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-09-26T19:34:53Z",
    "nvd_published_at": "2023-09-27T15:19:32Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n`_abi_decode()` does not validate input when it is nested in an expression. the following example gets correctly validated (bounds checked):\n```vyper\nx: int128 = _abi_decode(slice(msg.data, 4, 32), int128)\n```\n\nhowever, the following example is not bounds checked\n```vyper\n@external\ndef abi_decode(x: uint256) -\u003e uint256:\n    a: uint256 = convert(_abi_decode(slice(msg.data, 4, 32), (uint8)), uint256) + 1\n    return a  # abi_decode(256) returns: 257\n```\n\nthe issue can be triggered by constructing an example where the output of `_abi_decode` is not internally passed to `make_setter` (an internal codegen routine) or other input validating routine.\n\n### Patches\nhttps://github.com/vyperlang/vyper/pull/3626\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\n### References\n_Are there any links users can visit to find out more?_\n",
  "id": "GHSA-cx2q-hfxr-rj97",
  "modified": "2024-11-19T17:23:02Z",
  "published": "2023-09-26T19:34:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/vyperlang/vyper/security/advisories/GHSA-cx2q-hfxr-rj97"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-42460"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vyperlang/vyper/pull/3626"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2023-191.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/vyperlang/vyper"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Vyper\u0027s `_abi_decode` input not validated in complex expressions"
}


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