Drupal 6.x before 6.16 and 5.x before version 5.22 does not properly block users under certain circumstances. A user with an open session that was blocked could maintain their session on the Drupal site despite being blocked.
[
{
"product": "drupal6",
"vendor": "drupal6",
"versions": [
{
"status": "affected",
"version": "6.x before version 6.16"
},
{
"status": "affected",
"version": "5.x before version 5.22"
}
]
}
]