CVE-2026-45286CWE-200

Nextcloud: Calendar app leaked user identifiers via attendee suggestion endpoint

Medium · published June 1, 2026

CVSS v3.1
4.3
EPSS
0%
Percentile
38.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00456 · 38.6th percentile
Weakness
CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor
Published
2026-06-01T16:59Z
EPSS history
Timeline
  • 01 JUN 16:59Z
    Nextcloud: Calendar app leaked user identifiers via attendee suggestion endpoint
    cvelistv5