Security Advisory

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

Description

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

• Nextcloud Server < 9.0.52 (CVE-2016-9462)
• server/1208953ba1d4d55a18a639846bbcdd66a2d5bc5e

Action Taken

The permission check is now also performed on restore actions.

Resolution

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

Acknowledgements

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.