Security Advisory

Denial of Service attack (NC-SA-2017-004)

5th February 2017

Risk level: Low

CVSS v3 Base Score: 5 (AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L)

CWE: Uncontrolled Recursion (CWE-674)

HackerOne report: 174524

Description

Due to an error in the application logic an authenticated adversary may trigger an endless recursion in the application leading to a potential Denial of Service.

Affected Software

• Nextcloud Server < 10.0.2 (CVE-2017-0886)
• Nextcloud Server < 9.0.55 (CVE-2017-0886)

Action Taken

The code path leading to the endless recursion is now properly handled.

Resolution

It is recommended that all instances are upgraded to Nextcloud 9.0.55 or 10.0.2.

Acknowledgements

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

• secator - Vulnerability discovery and disclosure.

This advisory is licensed CC BY-SA 4.0.