CVE-2024-24564: Vyper Vyper's `extract32` Can Ready Dirty Vulnerability

LOW
Advisory Identifier: GHSA-4hwq-4cpm-8vmx
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CVSS 3.7
CWE-125
Published
Advisory Summary

CVE-2024-24564 is a LOW (CVSS 3.7) vyper's `extract32` can ready dirty vulnerability (CWE-125: Out-of-bounds Read) affecting Vyper libraries in the PyPI ecosystem. The issue involves vyper's `extract32` can ready dirty memory. Remediation is available by upgrading affected packages to version 0.4.0.

CVE-2024-24564 at a Glance

CVE Identifier CVE-2024-24564
GHSA Identifier GHSA-4hwq-4cpm-8vmx
Severity LOW
CVSS v3.1 Base Score 3.7
CWE Classification CWE-125: Out-of-bounds Read
Affected Product Vyper
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 3.7

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

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

How to Fix CVE-2024-24564

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-2024-24564, 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-125: Out-of-bounds Read, where the product reads data past the end, or before the beginning, of the intended buffer. 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 using the built-in `extract32(b, start)`, if the `start` index provided has for side effect to update `b`, the byte array to extract `32` bytes from, it could be that some dirty memory is read and returned by `extract32`. As of v0.4.0 (specifically, commit https://github.com/vyperlang/vyper/commit/3d9c537142fb99b2672f21e2057f5f202cde194f), the compiler will panic instead of generating bytecode. ### Details Before evaluating `start`, the function `Extract32.build_IR` caches only: - The pointer in memory/storage to `b`: https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L916-L918 - The length of `b`: https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L920-L922 but do not cache the actual content of `b`. This means that if the evaluation of `start` changes `b`'s content and length, an outdated length will be used with the new content when extracting 32 bytes from `b`. ### PoC Calling the function `foo` of the following contract returns `b'uuuuuuuuuuuuuuuuuuuuuuuuuuu\x00\x00789'` meaning that `extract32` accessed some dirty memory. ```Vyper var:Bytes[96] @internal def bar() -> uint256: self.var = b'uuuuuuuuuuuuuuuuuuuuuuuuuuuuuu' self.var = b'' return 3 @external def foo() -> bytes32: self.var = b'abcdefghijklmnopqrstuvwxyz123456789' return extract32(self.var, self.bar(), output_type=bytes32) # returns b'uuuuuuuuuuuuuuuuuuuuuuuuuuu\x00\x00789' ``` ### Impact For contracts that are affected, it means that calling `extract32` returns dirty memory bytes instead of some expected output.

CVE-2024-24564 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-4hwq-4cpm-8vmx
NVD — CVE-2024-24564 NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-24564
Security Fix Commit FIX COMMIT
https://github.com/vyperlang/vyper/commit/3d9c537142fb99b2672f21e2057f5f202cde194f
Vyper Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2024-205.yaml
Vyper Source Repository REPOSITORY
https://github.com/vyperlang/vyper
Vyper Source Repository REPOSITORY
https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L916-L918
Vyper Source Repository REPOSITORY
https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L920-L922

Frequently Asked Questions

What is CVE-2024-24564?
CVE-2024-24564 is a security vulnerability in Vyper involving Vyper's `extract32` can ready dirty memory under CWE-125: Out-of-bounds Read.
Which Vyper versions are affected?
Affected versions include releases prior to 0.4.0 across affected packages: vyper.
What version fixes CVE-2024-24564?
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-2024-24564?
CVE-2024-24564 has a CVSS v3.1 base score of 3.7 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2024-24564?
CVE-2024-24564 is classified under CWE-125: Out-of-bounds Read (The product reads data past the end, or before the beginning, of the intended buffer.).
How can I check PyPI dependencies for CVE-2024-24564?
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-4hwq-4cpm-8vmx",
  "modified" : "2025-01-21T17:54:09Z",
  "published" : "2024-02-26T20:11:35Z",
  "aliases" : [ "CVE-2024-24564" ],
  "summary" : "Vyper's `extract32` can ready dirty memory",
  "details" : "### Summary\n\nWhen using the built-in `extract32(b, start)`, if the `start` index provided has for side effect to update `b`, the byte array to extract `32` bytes from, it could be that some dirty memory is read and returned by `extract32`.\n\nAs of v0.4.0 (specifically, commit https://github.com/vyperlang/vyper/commit/3d9c537142fb99b2672f21e2057f5f202cde194f), the compiler will panic instead of generating bytecode.\n\n### Details\n\nBefore evaluating `start`, the function `Extract32.build_IR` caches only:\n\n- The pointer in memory/storage to `b`: https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L916-L918\n- The length of `b`: https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L920-L922\n\nbut do not cache the actual content of `b`. This means that if the evaluation of `start` changes `b`'s content and length, an outdated length will be used with the new content when extracting 32 bytes from `b`.\n\n### PoC\n\nCalling the function `foo` of the following contract returns `b'uuuuuuuuuuuuuuuuuuuuuuuuuuu\\x00\\x00789'` meaning that `extract32` accessed some dirty memory.\n\n```Vyper\nvar:Bytes[96]\n\n@internal\ndef bar() -> uint256:\n    self.var = b'uuuuuuuuuuuuuuuuuuuuuuuuuuuuuu'\n    self.var = b''\n    return 3\n\n@external\ndef foo() -> bytes32:\n    self.var = b'abcdefghijklmnopqrstuvwxyz123456789'\n    return extract32(self.var, self.bar(), output_type=bytes32)\n    # returns b'uuuuuuuuuuuuuuuuuuuuuuuuuuu\\x00\\x00789'\n```\n\n### Impact\n\nFor contracts that are affected, it means that calling `extract32` returns dirty memory bytes instead of some expected output.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "vyper"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.4.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.3.10"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/security/advisories/GHSA-4hwq-4cpm-8vmx"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2024-24564"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/commit/3d9c537142fb99b2672f21e2057f5f202cde194f"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2024-205.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vyperlang/vyper"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L916-L918"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L920-L922"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-125" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-02-26T20:11:35Z",
    "nvd_published_at" : "2024-02-26T20:19:05Z"
  }
}