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 sa…
Published: 2026-06-01 · CVSS: 4.3 · CVSS 3.1
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 to other endpoints, were not effective here. This issue has been patched in versions 5.5.17 and 6.2.3.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7