Auth bypass in Nextcloud Server

CVE-2016-9464

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.

EPSS: 0.016 (73.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

Affected products

  • Nextcloud Nextcloud_server — versions 10.0
  • N/a Nextcloud Server Before 9.0.54 And 10.0.0 — versions Nextcloud Server Nextcloud Server before 9.0.54 and 10.0.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2016-9464?
CVE-2016-9464 is a medium-severity vulnerability in Nextcloud Server, classified under Improper Authorization. CVSS score: 4.3/10. Published 2017-03-28.
How severe is CVE-2016-9464?
Medium severity. CVSS v3 base score is 4.3 out of 10.