A flaw was found in moodle before versions 3.5.1, 3.4.4, 3.3.7, 3.1.13. It was possible for the corecourseget_categories web service to return hidden categories, which should be omitted when fetching course categories.
{
"versions": [
{
"introduced": "3.1.0"
},
{
"fixed": "3.1.13"
},
{
"introduced": "3.3.0"
},
{
"fixed": "3.3.7"
},
{
"introduced": "3.4.0"
},
{
"fixed": "3.4.4"
},
{
"introduced": "3.5.0"
},
{
"fixed": "3.5.1"
}
]
}