Nextcloud Server before 9.0.55 and 10.0.2 suffers from a permission increase on re-sharing via OCS API issue. A permission related issue within the OCS sharing API allowed an authenticated adversary to reshare shared files with an increasing permission set. This may allow an attacker to edit files in a share despite having only a 'read' permission set. Note that this only affects folders and files that the adversary has at least read-only permissions for.
{
"versions": [
{
"introduced": "0"
},
{
"last_affected": "9.0.54"
},
{
"introduced": "0"
},
{
"last_affected": "10.0.2"
}
]
}