CVE-2026-45281

A flaw was found in Nextcloud Server. An authenticated user, with knowledge of another user's principal URL, could exploit improper authorization controls to gain full access to that user's calendar. This allows the attacker to view and modify the victim's calendar, leading to unauthorized...

CVE-2026-45281

CVE-2026-45281 affects Nextcloud Server versions 32.0.0–32.0.8 and 33.0.0–33.0.2. The issue stems from improper authorization in the calendar backend, requiring an authenticated attacker who knows another user’s principal URL. An authenticated user could potentially send a request to gain full ac...

CVE-2026-45281 Nextcloud: Cross-Account Calendar Takeover via Unauthorized Group-Member-Set Update

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, with the knowledge of other users’ principal URL an attacker could possibly send a request to gain full access to their calendar. Therefore, the...

CVE-2026-45281

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, with the knowledge of other users’ principal URL an attacker could possibly send a request to gain full access to their calendar. Therefore, the...