Nexkey is a lightweight fork of Misskey v12 optimized for small to medium size servers. Prior to 12.23Q4.5, Nexkey allows external apps using tokens issued by administrators and moderators to call admin APIs. This allows malicious third-party apps to perform operations such as updating server settings, as well as compromise object storage and email server credentials. This issue has been patched in 12.23Q4.5.
https://github.com/nexryai/nexkey/security/advisories/GHSA-pjj7-7hcj-9cpc
https://github.com/nexryai/nexkey/commit/a4e4c9c47c5f84ec7ccd309bde59d4ae5d7e5a98
https://github.com/misskey-dev/misskey/commit/5150053275594278e9eb23e72d98b16593c4c230
https://github.com/mei23/misskey-v12/commit/78173e376f14fcc1987b02196f5538bf5b18225c