CVE-2021-32728

Name: CVE-2021-32728
Creator: NVD / NIST
Published: 2021-08-18T16:15:07.293+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.85%

Last modified Jun 17, 2026

CVE-2021-32728 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.85% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

0.85%

53.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-295

Affected Software

Vendor	Product	Versions
Nextcloud	Desktop	< 3.3.0
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0

References

https://github.com/nextcloud/desktop/pull/3338Patch, Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5Exploit, Third Party Advisory
https://hackerone.com/reports/1189162Exploit, Third Party Advisory
https://www.debian.org/security/2021/dsa-4974Third Party Advisory
https://github.com/nextcloud/desktop/pull/3338Patch, Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5Exploit, Third Party Advisory
https://hackerone.com/reports/1189162Exploit, Third Party Advisory
https://www.debian.org/security/2021/dsa-4974Third Party Advisory

Timeline

Published: Aug 18, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-32728?

How severe is CVE-2021-32728?

CVE-2021-32728 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.85% probability of exploitation in the next 30 days.

How do I fix CVE-2021-32728?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-32728?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST