CVE-2026-45286

CVE-2026-45286 affects Nextcloud Open Source Content Collaboration Platform. An authenticated user could enumerate other users on the same instance by abusing the Calendar app’s endpoint for suggesting attendees; standard sharing restrictions did not apply to that endpoint. Impacted versions are ...

CVE-2026-45286 Nextcloud: Calendar app leaked user identifiers via attendee suggestion endpoint

Nextcloud is an open source content collaboration platform. From versions 5.5.13 to before 5.5.17, and 6.2.0 to before 6.2.3, an authenticated user can enumerate users on the same Nextcloud instance by using the Calendar app's endpoint for suggesting attendees. The sharing restrictions, applied t...