CVE-2021-32728

Public Exploit
End-to-end encryption device setup did not verify public key

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.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.45%
Vendor Advisory debian.org
Affected: nextcloud security-advisories
Published at:
Updated at:

References

Link Tags
https://hackerone.com/reports/1189162 third party advisory exploit
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5 third party advisory exploit
https://github.com/nextcloud/desktop/pull/3338 third party advisory patch
https://www.debian.org/security/2021/dsa-4974 third party advisory vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-32728?
CVE-2021-32728 has been scored as a medium severity vulnerability.
How to fix CVE-2021-32728?
To fix CVE-2021-32728, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-32728 being actively exploited in the wild?
It is possible that CVE-2021-32728 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-32728?
CVE-2021-32728 affects nextcloud security-advisories.
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