CVE-2026-45155: Nextcloud Security-Advisories

Low severity, CVSS 2.6. EPSS: 0.3% chance of exploitation in the next 30 days.

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.7 and 33.0.0 to before 33.0.1, a missing access check on API level allowed to add unknown circles by their ID directly to other circles. Since circle IDs have 62^15 complexity by default this is still unlikely to be executable at will, but if access to an ID was available via another source, memberships could be tracked like this. It is recommended that the Nextcloud Server is upgraded to 32.0.7 or 33.0.1. It is recommended that the Nextcloud Enterprise Server is upgraded to 29.0.16.14, 30.0.17.8, 31.0.14.3, 32.0.7 or 33.0.1

Affected products

• Nextcloud Security-Advisories: from 32.0.0, before 32.0.7 (fixed in 32.0.7); from 33.0.0, before 33.0.1 (fixed in 33.0.1)

Published 2026-06-01. Last modified 2026-07-22.