CVE-2021-32728 End-to-end encryption device setup did not verify public key

What is CVE-2021-32728?

CVE-2021-32728 is a medium-severity vulnerability in Debian Debian Linux, published on 18 Aug 2021. Any signed-in user can exploit it over the network, with no action from the victim.

Official 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.

Weakness: CWE-295

Which versions are affected by CVE-2021-32728?

It affects 2 products.

Products include Debian Debian Linux, Nextcloud Desktop.

How do I fix CVE-2021-32728?

Upgrade to a fixed version.

Is CVE-2021-32728 being exploited?

There is no known exploitation of CVE-2021-32728 in the wild and no public exploit code.

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All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-32728, GHSA-f5fr-5gcv-6cc5, UBUNTU-CVE-2021-32728.