high
7.5
CWE
190
Advisory Published
Advisory Published
Updated

CVE-2023-32058: Vyper vulnerable to integer overflow in loop

First published: Thu May 11 2023(Updated: )

### Impact Due to missing overflow check for loop variables, by assigning the iterator of a loop to a variable, it is possible to overflow the type of the latter. In the following example, calling `test` returns `354`, meaning that the variable `a` did store `354` a value out of bound for the type `uint8`. ```Vyper @external def test() -> uint16: x:uint8 = 255 a:uint8 = 0 for i in range(x, x+100): a = i return convert(a,uint16) ``` The issue seems to happen only in loops of type `for i in range(a, a + N)` as in loops of type `for i in range(start, stop)` and `for i in range(stop)`, the compiler is able to raise a `TypeMismatch` when trying to overflow the variable. thanks to @trocher for reporting ### Patches patched in 3de1415ee77a9244eb04bdb695e249d3ec9ed868 ### Workarounds

Credit: security-advisories@github.com security-advisories@github.com security-advisories@github.com

Affected SoftwareAffected VersionHow to fix
Vyperlang Vyper<0.3.8
pip/vyper<0.3.8
0.3.8

Remedy

https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868

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Reference Links

Frequently Asked Questions

  • What is CVE-2023-32058?

    CVE-2023-32058 is a vulnerability in the Vyper smart contract language for the Ethereum virtual machine that allows for an overflow of loop variables, potentially resulting in a type overflow.

  • How does CVE-2023-32058 affect Vyper?

    CVE-2023-32058 affects Vyper prior to version 0.3.8, where a missing overflow check for loop variables may lead to the overflow of the type of the variable.

  • What is the severity of CVE-2023-32058?

    The severity of CVE-2023-32058 is high, with a severity value of 7.5.

  • How can I fix CVE-2023-32058?

    To fix CVE-2023-32058, you should update Vyper to version 0.3.8 or later, which includes the necessary overflow check for loop variables.

  • What is the Common Weakness Enumeration (CWE) of CVE-2023-32058?

    The Common Weakness Enumeration (CWE) of CVE-2023-32058 is CWE-190, which relates to an integer overflow or wraparound.

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