Security Advisory

Back to advisories

Read-only share recipient can restore old versions of file (NC-SA-2016-005)

19th July 2016

Risk level: Low

CVSS v3 Base Score: 3.1 (AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N)

CWE: Permission Issues (CWE-275)

HackerOne report: 146067


The restore capability of Nextcloud was not verifying whether an user has only read-only access to a share. Thus an user with read-only access was able to restore old versions.

Affected Software

Action Taken

The permission check is now also performed on restore actions.


It is recommended that all instances are upgraded to Nextcloud 9.0.52.


The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory:

  • Rudra Pratap Singh - Vulnerability discovery and disclosure.

This advisory is licensed CC BY-SA 4.0.

You have javascript disabled. We tried to make sure the basics of our website work but some functionality will be missing.

This website is using cookies. By visiting you agree with our privacy policy. That's Fine