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Bypass lock protection in Android app (NC-SA-2019-008)

26th July 2019

Risk level: Low

CVSS v3 Base Score: 5.9 (AV:P/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N)

CWE: Authentication Bypass Using an Alternate Path or Channel (CWE-288)

HackerOne report: 507172


If an attacker has physical access to an Android smartphone without a screen lock, but with nextcloud installed and set up, they can circumvent the passcode protection by repeatedly opening and closing the app in a very short time.

Affected Software

  • Nextcloud Android < 3.6.1 (CVE-2019-5451)

Action Taken

The error has been fixed.


It is recommended that users upgrade to version 3.6.1 or later.


The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory:

  • Mathijs van Veluw - Vulnerability discovery and disclosure.

This advisory is licensed CC BY-SA 4.0.

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