CVE-2024-24563

Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine. Arrays can be keyed by a signed integer, while they are defined for unsigned integers only. The typechecker doesn't throw when spotting the usage of an `int` as an index for an array. The typechecker allows the usage of signed integers to be used as indexes to arrays. The vulnerability is present in different forms in all versions, including `0.3.10`. For ints, the 2's complement representation is used. Because the array was declared very large, the bounds checking will pass Negative values will simply be represented as very large numbers. As of time of publication, a fixed version does not exist. There are three potential vulnerability classes: unpredictable behavior, accessing inaccessible elements and denial of service. Class 1: If it is possible to index an array with a negative integer without reverting, this is most likely not anticipated by the developer and such accesses can cause unpredictable behavior for the contract. Class 2: If a contract has an invariant in the form `assert index < x`, the developer will suppose that no elements on indexes `y | y >= x` are accessible. However, by using negative indexes, this can be bypassed. Class 3: If the index is dependent on the state of the contract, this poses a risk of denial of service. If the state of the contract can be manipulated in such way that the index will be forced to be negative, the array access can always revert (because most likely the array won't be declared extremely large). However, all these the scenarios are highly unlikely. Most likely behavior is a revert on the bounds check.
Configurations

Configuration 1 (hide)

cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:python:*:*

History

15 Feb 2024, 05:02

Type Values Removed Values Added
References () https://github.com/vyperlang/vyper/blob/c150fc49ee9375a930d177044559b83cb95f7963/vyper/semantics/types/subscriptable.py#L127-L137 - () https://github.com/vyperlang/vyper/blob/c150fc49ee9375a930d177044559b83cb95f7963/vyper/semantics/types/subscriptable.py#L127-L137 - Product
References () https://github.com/vyperlang/vyper/blob/a1fd228cb9936c3e4bbca6f3ee3fb4426ef45490/vyper/codegen/core.py#L534-L541 - () https://github.com/vyperlang/vyper/blob/a1fd228cb9936c3e4bbca6f3ee3fb4426ef45490/vyper/codegen/core.py#L534-L541 - Product
References () https://github.com/vyperlang/vyper/security/advisories/GHSA-52xq-j7v9-v4v2 - () https://github.com/vyperlang/vyper/security/advisories/GHSA-52xq-j7v9-v4v2 - Exploit, Vendor Advisory
CPE cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:python:*:*
First Time Vyperlang
Vyperlang vyper
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 9.8

07 Feb 2024, 17:38

Type Values Removed Values Added
New CVE

Information

Published : 2024-02-07 17:15

Updated : 2024-02-28 20:54


NVD link : CVE-2024-24563

Mitre link : CVE-2024-24563

CVE.ORG link : CVE-2024-24563


JSON object : View

Products Affected

vyperlang

  • vyper
CWE
CWE-129

Improper Validation of Array Index