Improper Authorization in Nextcloud Server - CVE-2016-9464
Published: March 28, 2017 / Updated: July 18, 2020
Vulnerability identifier: #VU31435
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2016-9464
CWE-ID: CWE-285
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Nextcloud
Affected software:
Nextcloud Server
Nextcloud Server
Detailed vulnerability description
The vulnerability allows a remote authenticated user to manipulate data.
Nextcloud Server before 9.0.54 and 10.0.0 suffers from an improper authorization check on removing shares. The Sharing Backend as implemented in Nextcloud does differentiate between shares to users and groups. In case of a received group share, users should be able to unshare the file to themselves but not to the whole group. The previous API implementation simply unshared the file to all users in the group.
How to mitigate CVE-2016-9464
Install update from vendor's website.
Sources
- http://www.securityfocus.com/bid/97287
- https://github.com/nextcloud/server/commit/3387e5d00fcf6b2ea6b285a091e5743f545e7202
- https://github.com/nextcloud/server/commit/7289cb5ec0b812992ab0dfb889744b94bc0994f0
- https://github.com/nextcloud/server/commit/a5471b4a3e3f30e99e4de39c97c0c3b3c2f1618f
- https://github.com/nextcloud/server/commit/e2c4f4f9aa11bc92e8f2212cce73841b922187e8
- https://hackerone.com/reports/153905
- https://nextcloud.com/security/advisory/?id=nc-sa-2016-007