Nextcloud Server is an open source personal cloud server. Prior to versions 23.0.10 and 24.0.5, calendar name lengths are not validated before writing to a database. As a result, an attacker can send unnecessary amounts of data against the database. Version 23.0.10 and 24.0.5 contain patches for the issue. No known workarounds are available.
https://hackerone.com/reports/1596148
https://github.com/nextcloud/server/pull/33139
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m92j-xxc8-hq3v