Vulnerability · Published Jul 12, 2021 · Assigned by GitHub_M
CVE-2021-32727End-to-end encryption device setup did not verify public key
Medium 5.7
In plain English
A medium-severity improper certificate validation in security-advisories from nextcloud. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 55% of all known vulnerabilities).
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| nextcloud | security-advisories | < 3.16.1 |
Weakness: CWE-295 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
References
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736 x_refsource_CONFIRM
- https://github.com/nextcloud/android/pull/8438 x_refsource_MISC
- https://hackerone.com/reports/1189162 x_refsource_MISC
- https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices x_refsource_MISC