The WPS Hide Login WordPress plugin before 1.9.1 has a bug which allows to get the secret login page by setting a random referer string and making a request to /wp-admin/options.php as an unauthenticated user.
[
{
"product": "WPS Hide Login",
"vendor": "Unknown",
"versions": [
{
"lessThan": "1.9.1",
"status": "affected",
"version": "1.9.1",
"versionType": "custom"
}
]
}
]