Vulnerability in Nextcloud Server
CVE-2021-32656
Nextcloud Server is a Nextcloud package that handles data storage. A vulnerability in federated share exists in versions prior to 19.0.11, 20.0.10, and 21.0.2. An attacker can gain access to basic information about users of a server by accessing a public link that a legitimate server user added as a federated share. This happens because Nextcloud supports sharing registered users with other Nextcloud servers, which can be done automatically when selecting the "Add server automatically once a federated share was created successfully" setting. The vulnerability is patched in versions 19.0.11, 20.0.10, and 21.0.2 As a workaround, disable "Add server automatically once a federated share was created successfully" in the Nextcloud settings.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.018 (78.6th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 79th percentile — 78.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.018 · newest: 0.018 · change: 0.000
Affected products
- Nextcloud Server
- Nextcloud Security-Advisories — versions < 19.0.11, >= 20.0.0, < 20.0.10, >= 21.0.0, < 21.0.2
Weakness classification (CWE)
References
- github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6 (Third Party Advisory)
- hackerone.com/reports/1167853 (Permissions Required, Third Party Advisory)
- security.gentoo.org/glsa/202208-17 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-32656?
- CVE-2021-32656 is a high-severity vulnerability in Nextcloud Server, classified under Improper Access Control. CVSS score: 8.6/10. Published 2021-06-01.
- How severe is CVE-2021-32656?
- High severity. CVSS v3 base score is 8.6 out of 10.