CVE-2021-32727

5.7 MEDIUM 0.7% exploit odds Fix listed

What it is

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.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account, but needs a user to act. High risk of data exposure.
Exploit odds: 0.7% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-07-12 21:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:53 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.7% in the next 30 days (EPSS).
Severity: 5.7 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-07-12 21:15 UTC
Last modified: 2026-06-17 03:53 UTC
Exploit probability: 0.7% · EPSS, next 30 days
Weakness: CWE-295 · Improper certificate validation
Record status: Modified

Affected

Nextcloud < 3.16.1

Attack profile CVSS 3.1 · 5.7

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

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Fix and advisories

References

NVD record · CVE.org record