6.5
MEDIUM
CVE-2021-32728
Nextcloud Desktop Client Public Key Verification Vulnerability
Description

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.3.0, the Nextcloud Desktop client fails to check if a private key belongs to previously downloaded public certificate. If the Nextcloud instance serves a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. This issue is fixed in Nextcloud Desktop Client version 3.3.0. There are no known workarounds aside from upgrading.

INFO

Published Date :

Aug. 18, 2021, 4:15 p.m.

Last Modified :

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

Remotely Exploitable :

Yes !

Impact Score :

3.6

Exploitability Score :

2.8
Affected Products

The following products are affected by CVE-2021-32728 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 desktop
2 Nextcloud nextcloud_server
3 Nextcloud notes
1 Debian debian_linux
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-2021-32728.

URL Resource
https://github.com/nextcloud/desktop/pull/3338 Patch Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5 Exploit Third Party Advisory
https://hackerone.com/reports/1189162 Exploit Third Party Advisory
https://www.debian.org/security/2021/dsa-4974 Third Party Advisory
https://github.com/nextcloud/desktop/pull/3338 Patch Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5 Exploit Third Party Advisory
https://hackerone.com/reports/1189162 Exploit Third Party Advisory
https://www.debian.org/security/2021/dsa-4974 Third Party Advisory

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-2021-32728 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-32728 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/desktop/pull/3338
    Added Reference https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5
    Added Reference https://hackerone.com/reports/1189162
    Added Reference https://www.debian.org/security/2021/dsa-4974
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Reanalysis by [email protected]

    Oct. 04, 2022

    Action Type Old Value New Value
    Changed Reference Type https://hackerone.com/reports/1189162 Permissions Required, Third Party Advisory https://hackerone.com/reports/1189162 Exploit, Third Party Advisory
    Changed CPE Configuration OR *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* versions up to (excluding) 3.3.0 OR *cpe:2.3:a:nextcloud:desktop:*:*:*:*:*:*:*:* versions up to (excluding) 3.3.0
  • Reanalysis by [email protected]

    Sep. 27, 2022

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:nextcloud:nextcloud:*:*:*:*:*:*:*:* versions up to (excluding) 3.3.0 OR *cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:* versions up to (excluding) 3.3.0
  • Modified Analysis by [email protected]

    Dec. 16, 2021

    Action Type Old Value New Value
    Changed Reference Type https://www.debian.org/security/2021/dsa-4974 No Types Assigned https://www.debian.org/security/2021/dsa-4974 Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* *cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Sep. 20, 2021

    Action Type Old Value New Value
    Added Reference https://www.debian.org/security/2021/dsa-4974 [No Types Assigned]
  • Initial Analysis by [email protected]

    Aug. 24, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:S/C:P/I:N/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
    Changed Reference Type https://github.com/nextcloud/desktop/pull/3338 No Types Assigned https://github.com/nextcloud/desktop/pull/3338 Patch, Third Party Advisory
    Changed Reference Type https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5 No Types Assigned https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5 Exploit, Third Party Advisory
    Changed Reference Type https://hackerone.com/reports/1189162 No Types Assigned https://hackerone.com/reports/1189162 Permissions Required, Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:nextcloud:nextcloud:*:*:*:*:*:*:*:* versions up to (excluding) 3.3.0
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.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-32728 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-2021-32728 weaknesses.

Exploit Prediction

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

0.45 }} -0.41%

score

0.74818

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability