CVE-2026-45155: 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 m...

Description

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

Metrics

CVSS 3.1

2.6/10

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N

EPSS Probability

0.20%

10.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-639

References

Timeline

Published: Jun 1, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-45155?

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

How severe is CVE-2026-45155?

CVE-2026-45155 has a CVSS score of 2.6/10 (LOW severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-45155?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.