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CVE PROGRAM SOURCE RECORD4.3 Medium

CVE-2026-45286

Nextcloud: Calendar app leaked user identifiers via attendee suggestion endpoint

Description

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

nextcloud security-advisories

  • >= 5.5.13, < 5.5.17affected
  • >= 6.2.0, < 6.2.3affected

References