CVE-2024-32481: Vyper Vyper's Range(start, Start + N) Vulnerability

MODERATE
Advisory Identifier: GHSA-ppx5-q359-pvwj
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CVSS 5.3
CWE-681
Published
Advisory Summary

CVE-2024-32481 is a MODERATE (CVSS 5.3) vyper's range(start, start + n) vulnerability (CWE-681: Incorrect Conversion between Numeric Types) affecting Vyper libraries in the PyPI ecosystem. The issue involves vyper's range(start, start + n) reverts for negative numbers. Remediation is available by upgrading affected packages to version 0.4.0.

CVE-2024-32481 at a Glance

CVE Identifier CVE-2024-32481
GHSA Identifier GHSA-ppx5-q359-pvwj
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-681: Incorrect Conversion between Numeric Types
Affected Product Vyper
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2024-32481

To remediate this vulnerability, upgrade all affected Vyper dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

vyper fixed: 0.4.0 
pip install vyper>=0.4.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show vyper

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2024-32481, inspect your installed packages using pip:

pip show vyper

Analyze the terminal output to locate any version of Vyper in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.4.0), your application is affected.

Note: The pip show vyper command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-681: Incorrect Conversion between Numeric Types, where when converting from one data type to another, such as long to integer, data can be omitted or translated in a way that produces unexpected values. if the resulting values are used in a sensitive context, then dangerous behaviors may occur. In Vyper, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary When looping over a `range` of the form `range(start, start + N)`, if `start` is negative, the execution will always revert. ### Details This issue is caused by an incorrect assertion inserted by the code generation of the range (`stmt.parse_For_range()`): https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287 This 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. ### PoC ```Vyper @external def foo(): x:int256 = min_value(int256) # revert when it should not since we have the following assertion that fails: # [assert, [le, min_value(int256), max_value(int256) + 1 - 10]], for i in range(x, x + 10): pass ``` ### Patches patched in v0.4.0, specifically, https://github.com/vyperlang/vyper/pull/3679 disallows this form of `range()`. ### Impact 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.

CVE-2024-32481 Affected Vyper Versions

1 component(s)
Fixed Versions:
0.4.0
Product / Package Ecosystem Affected Versions Fixed Version
vyper
pypi/vyper
PyPI
≥ 0.3.8
< 0.4.0
0.4.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vyperlang/vyper/security/advisories/GHSA-ppx5-q359-pvwj
NVD — CVE-2024-32481 NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-32481
Security Fix Commit FIX COMMIT
https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868
Security Fix Commit FIX COMMIT
https://github.com/vyperlang/vyper/commit/5319cfbe14951e007ccdb323257e5ada869b35d5
Vyper Source Repository REPOSITORY
https://github.com/vyperlang/vyper
Vyper Source Repository REPOSITORY
https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287

Frequently Asked Questions

What is CVE-2024-32481?
CVE-2024-32481 is a security vulnerability in Vyper involving vyper's range(start, start + N) reverts for negative numbers under CWE-681: Incorrect Conversion between Numeric Types.
Which Vyper versions are affected?
Affected versions include releases prior to 0.4.0 across affected packages: vyper.
What version fixes CVE-2024-32481?
Upgrading to 0.4.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is vyper affected?
Yes, vyper is affected in releases prior to 0.4.0. Upgrade your dependency to 0.4.0 or later.
What is the CVSS score of CVE-2024-32481?
CVE-2024-32481 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2024-32481?
CVE-2024-32481 is classified under CWE-681: Incorrect Conversion between Numeric Types (When converting from one data type to another, such as long to integer, data can be omitted or translated in a way that produces unexpected values. If the resulting values are used in a sensitive context, then dangerous behaviors may occur.).
How can I check PyPI dependencies for CVE-2024-32481?
Run the dependency tree command: 'pip show vyper'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-ppx5-q359-pvwj",
  "modified" : "2024-04-25T19:53:43Z",
  "published" : "2024-04-25T19:53:43Z",
  "aliases" : [ "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
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      "name" : "vyper"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.3.8"
      }, {
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      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
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    "type" : "ADVISORY",
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  }, {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/commit/5319cfbe14951e007ccdb323257e5ada869b35d5"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vyperlang/vyper"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-681" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-25T19:53:43Z",
    "nvd_published_at" : "2024-04-25T17:15:50Z"
  }
}