The Simple Membership WordPress plugin before 4.1.3 allows user to change their membership at the registration stage due to insufficient checking of a user supplied parameter.
[
{
"product": "Simple Membership",
"vendor": "Unknown",
"versions": [
{
"lessThan": "4.1.3",
"status": "affected",
"version": "4.1.3",
"versionType": "custom"
}
]
}
]