Misskey is an open source, federated social media platform.In affected versions missing validation in `NoteCreateService.insertNote`, `ApPersonService.createPerson`, and `ApPersonService.updatePerson` allows an attacker to control the target of any "origin" links (such as the "view on remote instance" banner). Any HTTPS URL can be set, even if it belongs to a different domain than the note / user. Vulnerable Misskey instances will use the unverified URL for several clickable links, allowing an attacker to conduct phishing or other attacks against remote users. This issue has been addressed in version 2024.11.0-alpha.3. Users are advised to upgrade. There are no known workarounds for this vulnerability.