GHSA-3P37-3636-Q8WV

Vulnerability from github – Published: 2023-05-12 20:21 – Updated: 2024-11-19 16:32
VLAI?
Summary
Vyper vulnerable to OOB DynArray access when array is on both LHS and RHS of an assignment
Details

Impact

during codegen, the length word of a dynarray is written before the data, which can result in OOB array access in the case where the dynarray is on both the lhs and rhs of an assignment. here is a minimal example producing the issue:

a:DynArray[uint256,3]
@external
def test() -> DynArray[uint256,3]:
    self.a = [1,2,3]
    self.a = empty(DynArray[uint256,3])
    self.a = [self.a[0],self.a[1],self.a[2]]
    return self.a # return [1,2,3]

and here is an example demonstrating the issue can cause data corruption across call frames:

@external
def test() -> DynArray[uint256,3]:
    self.a()
    return self.b() # return [1,2,3]

@internal
def a():
    a: uint256 = 0    
    b: uint256 = 1    
    c: uint256 = 2    
    d: uint256 = 3

@internal
def b() -> DynArray[uint256,3]:
    a: DynArray[uint256,3] = empty(DynArray[uint256,3])
    a = [a[0],a[1],a[2]]
    return a

examples involving append and pop:

@internal
def foo():
    c: DynArray[uint256, 1] = []
    c.append(c[0])

@internal
def foo():
    c: DynArray[uint256, 1] = [1]
    c[0] = c.pop()

the expected behavior in all of the above cases is to revert due to oob array access.

Patches

patched in 4f8289a81206f767df1900ac48f485d90fc87edb

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 ?
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
8.7 (High)
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
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "vyper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.3.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-31146"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-05-12T20:21:54Z",
    "nvd_published_at": "2023-05-11T21:15:10Z",
    "severity": "HIGH"
  },
  "details": "### Impact\nduring codegen, the length word of a dynarray is written before the data, which can result in OOB array access in the case where the dynarray is on both the lhs and rhs of an assignment. here is a minimal example producing the issue:\n```vyper\na:DynArray[uint256,3]\n@external\ndef test() -\u003e DynArray[uint256,3]:\n    self.a = [1,2,3]\n    self.a = empty(DynArray[uint256,3])\n    self.a = [self.a[0],self.a[1],self.a[2]]\n    return self.a # return [1,2,3]\n```\n\nand here is an example demonstrating the issue can cause data corruption across call frames:\n\n```vyper\n@external\ndef test() -\u003e DynArray[uint256,3]:\n    self.a()\n    return self.b() # return [1,2,3]\n\n@internal\ndef a():\n    a: uint256 = 0    \n    b: uint256 = 1    \n    c: uint256 = 2    \n    d: uint256 = 3\n\n@internal\ndef b() -\u003e DynArray[uint256,3]:\n    a: DynArray[uint256,3] = empty(DynArray[uint256,3])\n    a = [a[0],a[1],a[2]]\n    return a\n```\n\nexamples involving append and pop:\n```vyper\n@internal\ndef foo():\n    c: DynArray[uint256, 1] = []\n    c.append(c[0])\n```\n\n```vyper\n@internal\ndef foo():\n    c: DynArray[uint256, 1] = [1]\n    c[0] = c.pop()\n```\n\nthe expected behavior in all of the above cases is to revert due to oob array access.\n\n### Patches\npatched in 4f8289a81206f767df1900ac48f485d90fc87edb\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-3p37-3636-q8wv",
  "modified": "2024-11-19T16:32:12Z",
  "published": "2023-05-12T20:21:54Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/vyperlang/vyper/security/advisories/GHSA-3p37-3636-q8wv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-31146"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vyperlang/vyper/commit/4f8289a81206f767df1900ac48f485d90fc87edb"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2023-77.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/vyperlang/vyper"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Vyper vulnerable to OOB DynArray access when array is on both LHS and RHS of an assignment"
}


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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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