Mastodon through 4.0.2 allows attackers to cause a denial of service (large Sidekiq pull queue) by creating bot accounts that follow attacker-controlled accounts on certain other servers associated with a wildcard DNS A record, such that there is uncontrolled recursion of attacker-generated messages.
{
"cpes": [
"cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*"
],
"severity": "High"
}