CVE-2024-32649: Vyper Vyper Performs Multiple Eval Of Vulnerability

MODERATE
Advisory Identifier: GHSA-5jrj-52x8-m64h
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CVSS 5.3
CWE-95
Published
Advisory Summary

CVE-2024-32649 is a MODERATE (CVSS 5.3) vyper performs multiple eval of vulnerability (CWE-95: Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')) affecting Vyper libraries in the PyPI ecosystem. The issue involves vyper performs multiple eval of `sqrt()` argument built in. Remediation is available by upgrading affected packages to version 0.4.0.

CVE-2024-32649 at a Glance

CVE Identifier CVE-2024-32649
GHSA Identifier GHSA-5jrj-52x8-m64h
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-95: Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')
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-2024-32649

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-2024-32649, 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-95: Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection'), where the product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. "eval"). 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 Using the `sqrt` builtin can result in multiple eval evaluation of side effects when the argument has side-effects. The bug is more difficult (but not impossible!) to trigger as of 0.3.4, when the unique symbol fence was introduced (https://github.com/vyperlang/vyper/pull/2914). A contract search was performed and no vulnerable contracts were found in production. ### Details It can be seen that the `build_IR` function of the `sqrt` builtin doesn't cache the argument to the stack: https://github.com/vyperlang/vyper/blob/4595938734d9988f8e46e8df38049ae0559abedb/vyper/builtins/functions.py#L2151 As such, it can be evaluated multiple times (instead of retrieving the value from the stack). ### PoC With at least Vyper version `0.2.15+commit.6e7dba7` the following contract: ```vyper c: uint256 @internal def some_decimal() -> decimal: self.c += 1 return 1.0 @external def foo() -> uint256: k: decimal = sqrt(self.some_decimal()) return self.c ``` passes the following test: ```solidity // SPDX-License-Identifier: MIT pragma solidity >=0.8.13; import "../../lib/ds-test/test.sol"; import "../../lib/utils/Console.sol"; import "../../lib/utils/VyperDeployer.sol"; import "../ITest.sol"; contract ConTest is DSTest { VyperDeployer vyperDeployer = new VyperDeployer(); ITest t; function setUp() public { t = ITest(vyperDeployer.deployContract("Test")); } function testFoo() public { uint256 val = t.foo(); console.log(val); assert (val == 4); } } ``` ### Patches Patched in https://github.com/vyperlang/vyper/pull/3976. ### Impact No vulnerable production contracts were found.

CVE-2024-32649 Affected Vyper Versions

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

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vyperlang/vyper/security/advisories/GHSA-5jrj-52x8-m64h
NVD — CVE-2024-32649 NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-32649
Vyper Source Repository REPOSITORY
https://github.com/vyperlang/vyper/pull/2914
Vyper Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2024-209.yaml
Vyper Source Repository REPOSITORY
https://github.com/vyperlang/vyper

Frequently Asked Questions

What is CVE-2024-32649?
CVE-2024-32649 is a security vulnerability in Vyper involving vyper performs multiple eval of `sqrt()` argument built in under CWE-95: Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection').
Which Vyper versions are affected?
Affected versions include releases prior to 0.4.0 across affected packages: vyper.
What version fixes CVE-2024-32649?
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-2024-32649?
CVE-2024-32649 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-2024-32649?
CVE-2024-32649 is classified under CWE-95: Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection') (The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. "eval").).
How can I check PyPI dependencies for CVE-2024-32649?
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-5jrj-52x8-m64h",
  "modified" : "2025-01-21T17:53:44Z",
  "published" : "2024-04-25T19:50:16Z",
  "aliases" : [ "CVE-2024-32649" ],
  "summary" : "vyper performs multiple eval of `sqrt()` argument built in",
  "details" : "### Summary\nUsing the `sqrt` builtin can result in multiple eval evaluation of side effects when the argument has side-effects. The bug is more difficult (but not impossible!) to trigger as of 0.3.4, when the unique symbol fence was introduced (https://github.com/vyperlang/vyper/pull/2914).\n\nA contract search was performed and no vulnerable contracts were found in production.\n\n### Details\nIt can be seen that the `build_IR` function of the `sqrt` builtin doesn't cache the argument to the stack: \nhttps://github.com/vyperlang/vyper/blob/4595938734d9988f8e46e8df38049ae0559abedb/vyper/builtins/functions.py#L2151\n\nAs such, it can be evaluated multiple times (instead of retrieving the value from the stack).\n\n### PoC\nWith at least Vyper version `0.2.15+commit.6e7dba7` the following contract:\n```vyper\nc: uint256\n\n@internal\ndef some_decimal() -> decimal:\n    self.c += 1\n    return 1.0\n\n@external\ndef foo() -> uint256:\n    k: decimal = sqrt(self.some_decimal())\n    return self.c\n```\npasses the following test:\n```solidity\n// SPDX-License-Identifier: MIT\npragma solidity >=0.8.13;\n\nimport \"../../lib/ds-test/test.sol\";\nimport \"../../lib/utils/Console.sol\";\nimport \"../../lib/utils/VyperDeployer.sol\";\n\nimport \"../ITest.sol\";\n\ncontract ConTest is DSTest {\n    VyperDeployer vyperDeployer = new VyperDeployer();\n\n    ITest t;\n\n    function setUp() public {\n        t = ITest(vyperDeployer.deployContract(\"Test\"));\n    }\n\n    function testFoo() public {\n        uint256 val = t.foo();\n        console.log(val);\n        assert (val == 4);\n    }\n}\n```\n \n### Patches\nPatched in https://github.com/vyperlang/vyper/pull/3976.\n\n### Impact\nNo vulnerable production contracts were found.",
  "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" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "vyper"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.4.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/security/advisories/GHSA-5jrj-52x8-m64h"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2024-32649"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/pull/2914"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2024-209.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vyperlang/vyper"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-95" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-25T19:50:16Z",
    "nvd_published_at" : "2024-04-25T18:15:09Z"
  }
}