Nextcloud Server <32.0.7 & <33.0.1 Circle Privilege Escalation
CVE-2026-45155 Published on June 1, 2026
Nextcloud: Private circle can be added to another circle via API
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
Vulnerability Analysis
CVE-2026-45155 can be exploited with network access, requires user interaction and a small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a small impact on integrity and availability.
Weakness Type
What is an Insecure Direct Object Reference / IDOR Vulnerability?
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
CVE-2026-45155 has been classified to as an Insecure Direct Object Reference / IDOR vulnerability or weakness.
Affected Versions
nextcloud security-advisories:- Version >= 32.0.0, < 32.0.7 is affected.
- Version >= 33.0.0, < 33.0.1 is affected.