PT-2021-19834 · Nextcloud+1 · Nextcloud Server+1

Rtod · Published 2021-06-01 · Updated 2022-10-25 · CVE-2021-32656

Positive Technologies (AI Summary)

CVSS v3.1

8.6

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Name of the Vulnerable Software and Affected Versions Nextcloud Server versions prior to 19.0.11 Nextcloud Server versions prior to 20.0.10 Nextcloud Server versions prior to 21.0.2

Description A vulnerability in federated share exists in Nextcloud Server, allowing an attacker to 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 occurs 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.

Recommendations For versions prior to 19.0.11, update to version 19.0.11 or later. For versions prior to 20.0.10, update to version 20.0.10 or later. For versions prior to 21.0.2, update to version 21.0.2 or later. As a temporary workaround, consider disabling the "Add server automatically once a federated share was created successfully" setting in the Nextcloud settings.

Fix

Improper Access Control

Weakness Enumeration

CWE-284

Related Identifiers

ALT-PU-2021-3108

ALT-PU-2021-3224

CVE-2021-32656

GHSA-J875-VR2Q-H6X6

Affected Products

Alt Linux

Nextcloud Server

References · 7

• https://osv.dev/vulnerability/CVE-2021-32656 · Vendor Advisory
• https://security.gentoo.org/glsa/202208-17 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-32656 · Security Note
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6 · Note
• https://t.me/cvenotify/34528 · Telegram Post
• https://t.me/cvenotify/15363 · Telegram Post
• https://hackerone.com/reports/1167853 · Note