Vulnerability in Nextcloud Server
CVE-2023-35927
NextCloud Server and NextCloud Enterprise Server provide file storage for Nextcloud, a self-hosted productivity platform. In NextCloud Server versions 25.0.0 until 25.0.7 and 26.0.0 until 26.0.2 and Nextcloud Enterprise Server versions 21.0.0 until 21.0.9.12, 22.0.0 until 22.2.10.12, 23.0.0 until 23.0.12.7, 24.0.0 until 24.0.12.2, 25.0.0 until 25.0.7, and 26.0.0 until 26.0.2, when two server are registered as trusted servers for each other and successfully exchanged the share secrets, the malicious server could modify or delete VCards in the system addressbook on the origin server. This would impact the available and shown information in certain places, such as the user search and avatar menu. If a manipulated user modifies their own data in the personal settings the entry is fixed again. Nextcloud Server n 25.0.7 and 26.0.2 and Nextcloud Enterprise Server 21.0.9.12, 22.2.10.12, 23.0.12.7, 24.0.12.2, 25.0.7, and 26.0.2 contain a patch for this issue. A workaround is available. Remove all trusted servers in the "Administration" > "Sharing" settings `…/index.php/settings/admin/sharing`. Afterwards, trigger a recreation of the local system addressbook with the following `occ dav:sync-system-addressbook`.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:L.
EPSS exploit prediction
EPSS: 0.008 (55.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 55.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000
Affected products
- Nextcloud Server
- Nextcloud Security-Advisories — versions Nextcloud Server >= 25.0.0, < 25.0.7, Nextcloud Server >= 26.0.0, < 26.0.2, Nextcloud Enterprise Server >= 25.0.0, < 25.0.7
Weakness classification (CWE)
References
- github.com/nextcloud/security-advisories/security/advisories/GHSA-h7f7-535f-7q87 (Vendor Advisory)
- github.com/nextcloud/server/pull/38247 (Issue Tracking)
- hackerone.com/reports/1976754 (Permissions Required)
Frequently asked questions
- What is CVE-2023-35927?
- CVE-2023-35927 is a high-severity vulnerability in Nextcloud Server, classified under Improper Access Control. CVSS score: 7.6/10. Published 2023-06-23.
- How severe is CVE-2023-35927?
- High severity. CVSS v3 base score is 7.6 out of 10.