CVE-2021-32728

moderate-risk
Published 2021-08-18

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.

Do I need to act?

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0.21% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
6
CVSS 6.5/10 Medium
NETWORK / LOW complexity

Affected Products (3)

Affected Vendors

Debian Nextcloud

References (8)

Patch https://github.com/nextcloud/desktop/pull/3338
Exploit https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5...
Exploit https://hackerone.com/reports/1189162
Third Party Advisory https://www.debian.org/security/2021/dsa-4974
Patch https://github.com/nextcloud/desktop/pull/3338
Exploit https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5...
Exploit https://hackerone.com/reports/1189162
Third Party Advisory https://www.debian.org/security/2021/dsa-4974
34
/ 100
moderate-risk
Severity 24/34 · High
Exploitability 1/34 · Minimal
Exposure 9/34 · Low