CVE-2021-32727 End-to-end encryption device setup did not verify public key
Attackers can bypass end-to-end encryption verification to access encrypted data if a malicious public key is served by the Nextcloud instance.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-32727?
CVE-2021-32727 is a medium-severity vulnerability in nextcloud security-advisories, published on 12 Jul 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Nextcloud Android Client is the Android client for Nextcloud. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account.
Weakness: CWE-295
Which versions are affected by CVE-2021-32727?
1 open source package ship an affected version, including nextcloud. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
nextcloud Bitnami | All versions | 3.16.1 |
Products include Nextcloud Nextcloud.
How do I fix CVE-2021-32727?
Upgrade nextcloud to 3.16.1 or later.
Is CVE-2021-32727 being exploited?
There is no known exploitation of CVE-2021-32727 in the wild and no public exploit code.
Other vulnerabilities in nextcloud security-advisories
- CVE-2019-5454 SQL injection in com.nextcloud.client
- CVE-2021-43863 SQL Injection in FileContentProvider (GHSL-2021-1007)
- CVE-2019-5450 Cross-site scripting in com.nextcloud.client
- CVE-2019-5455 Auth bypass in com.nextcloud.client
- CVE-2021-22905 Information disclosure in Nextcloud Android App (com.nextcloud.client)
Sources
Also known as BIT-nextcloud-2021-32727, GHSA-5v33-r9cm-7736.