title: Incorrect Comparison in Vyper
description: Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine. In version 0.3.1 and prior, bytestrings can have dirty bytes in them, resulting in the word-for-word comparisons giving incorrect results. Even without dirty nonzero bytes, two bytestrings can compare to equal if one ends with `"\x00"` because there is no comparison of the length. A patch is available and expected to be part of the 0.3.2 release. There are currently no known workarounds.
problem types: CWE-697: Incorrect Comparison
affected:
{
product: vyper
vendor: vyperlang
versions:
status: affected, version: <= 0.3.1
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 7.5
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: HIGH
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
version: 3.1
]