Security Advisory

Missing URL validation allowed RCE for the server on the Desktop client (NC-SA-2021-008)

24th February 2021

Risk level: Low

CVSS v3 Base Score: 4.7 (AV:L/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:L)

CWE: Resource Injection (CWE-99)

HackerOne report: 1078002

Description

Missing validation of URLs in Nextcloud Desktop Client 3.1.2 and earlier allowed a malicious server to execute code on the client. User interaction was required.

Affected Software

• Nextcloud Desktop < 3.1.3 (CVE-2021-22879)

Action Taken

The error has been fixed.

Resolution

It is recommended that the Nextcloud Desktop Client is upgraded to 3.1.3.

Acknowledgements

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

• Fabian Bräunlein - Positive Security - Vulnerability discovery and disclosure.

This advisory is licensed CC BY-SA 4.0.