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8.6
HIGH CVSS 3.1
CVE-2021-32656
Trusted servers exchange can be triggered by attacker
Description

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.

INFO

Published Date :

June 1, 2021, 10:15 p.m.

Last Modified :

Nov. 21, 2024, 6:07 a.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2021-32656 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Nextcloud nextcloud_server
2 Nextcloud notes
: Total Affected Vendor : 1 | Products : 2
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 MEDIUM [email protected]
CVSS 3.1 HIGH [email protected]
CVSS 3.1 HIGH [email protected]
Solution
This information is provided by the 3rd party feeds.
  • All Nextcloud users should upgrade to the latest version: # emerge --sync # emerge --ask --oneshot --verbose >=www-apps/nextcloud-23.0.4
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-32656.

URL Resource
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6 Third Party Advisory
https://hackerone.com/reports/1167853 Permissions Required Third Party Advisory
https://security.gentoo.org/glsa/202208-17 Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6 Third Party Advisory
https://hackerone.com/reports/1167853 Permissions Required Third Party Advisory
https://security.gentoo.org/glsa/202208-17 Third Party Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-32656 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-32656 weaknesses.

CAPEC-19: Embedding Scripts within Scripts Embedding Scripts within Scripts CAPEC-441: Malicious Logic Insertion Malicious Logic Insertion CAPEC-478: Modification of Windows Service Configuration Modification of Windows Service Configuration CAPEC-479: Malicious Root Certificate Malicious Root Certificate CAPEC-502: Intent Spoof Intent Spoof CAPEC-503: WebView Exposure WebView Exposure CAPEC-536: Data Injected During Configuration Data Injected During Configuration CAPEC-546: Incomplete Data Deletion in a Multi-Tenant Environment Incomplete Data Deletion in a Multi-Tenant Environment CAPEC-550: Install New Service Install New Service CAPEC-551: Modify Existing Service Modify Existing Service CAPEC-552: Install Rootkit Install Rootkit CAPEC-556: Replace File Extension Handlers Replace File Extension Handlers CAPEC-558: Replace Trusted Executable Replace Trusted Executable CAPEC-562: Modify Shared File Modify Shared File CAPEC-563: Add Malicious File to Shared Webroot Add Malicious File to Shared Webroot CAPEC-564: Run Software at Logon Run Software at Logon CAPEC-578: Disable Security Software Disable Security Software

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-32656 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2021-32656 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6
    Added Reference https://hackerone.com/reports/1167853
    Added Reference https://security.gentoo.org/glsa/202208-17
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Modified Analysis by [email protected]

    Oct. 25, 2022

    Action Type Old Value New Value
    Changed Reference Type https://security.gentoo.org/glsa/202208-17 No Types Assigned https://security.gentoo.org/glsa/202208-17 Third Party Advisory
    Added CWE NIST NVD-CWE-Other
  • CVE Modified by [email protected]

    Aug. 11, 2022

    Action Type Old Value New Value
    Added Reference https://security.gentoo.org/glsa/202208-17 [No Types Assigned]
  • Initial Analysis by [email protected]

    Jun. 11, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:N/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
    Changed Reference Type https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6 No Types Assigned https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6 Third Party Advisory
    Changed Reference Type https://hackerone.com/reports/1167853 No Types Assigned https://hackerone.com/reports/1167853 Permissions Required, Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* versions up to (excluding) 19.0.11 *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* versions from (including) 20.0.0 up to (excluding) 20.0.10 *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* versions from (including) 21.0.0 up to (excluding) 21.0.2
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 8.6
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 5
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.46 }} 0.12%

score

0.63351

percentile