Mattermost versions 9.10.x <= 9.10.2, 9.11.x <= 9.11.1, 9.5.x <= 9.5.9 and 10.0.x <= 10.0.0 fail to properly authorize the requests to /api/v4/channels which allows a User or System Manager, with "Read Groups" permission but with no access for channels to retrieve details about private channels that they were not a member of by sending a request to /api/v4/channels.
{
"versions": [
{
"introduced": "9.5.0"
},
{
"fixed": "9.5.10"
},
{
"introduced": "9.10.0"
},
{
"fixed": "9.10.3"
},
{
"introduced": "9.11.0"
},
{
"fixed": "9.11.2"
},
{
"introduced": "0"
},
{
"last_affected": "10.0.0-NA"
},
{
"introduced": "0"
},
{
"last_affected": "10.0.0-rc1"
},
{
"introduced": "0"
},
{
"last_affected": "10.0.0-rc2"
},
{
"introduced": "0"
},
{
"last_affected": "10.0.0-rc3"
},
{
"introduced": "0"
},
{
"last_affected": "10.0.0-rc4"
}
]
}