BIT-MASTODON-2026-23963 Mastodon missing length limits on list names, filter names, and filter keywords

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.5, 4.4.12, and 4.3.18, the server does not enforce a maximum length for the names of lists or filters, or for filter keywords, allowing any user to set an arbitrarily long string as the name or...

CVE-2026-23963

CVE-2026-23963 affects Mastodon prior to versions 4.5.5, 4.4.12, and 4.3.18 where there is no maximum length enforcement for list names, filter names, or filter keywords. This can enable a local user to craft arbitrarily long strings, leading to disproportionate storage and compute resource usage...