Mattermost versions 9.11.x <= 9.11.0 and 9.5.x <= 9.5.8 fail to validate that the message of the permalink post is a string, which allows an attacker to send a non-string value as the message of a permalink post and crash the frontend.
{
"versions": [
{
"introduced": "9.5.0"
},
{
"fixed": "9.5.9"
},
{
"introduced": "0"
},
{
"last_affected": "9.11.0-NA"
},
{
"introduced": "0"
},
{
"last_affected": "9.11.0-rc1"
},
{
"introduced": "0"
},
{
"last_affected": "9.11.0-rc2"
},
{
"introduced": "0"
},
{
"last_affected": "9.11.0-rc3"
}
]
}