CVE-2021-41166

Permission bypass in Nextcloud Android App

4.3 MediumFix available

The Nextcloud Android app is the Android client for Nextcloud, a self-hosted productivity platform. An issue in versions prior to 3.17.1 may lead to sensitive information disclosure. An unauthorized app that does not have the otherwise required MANAGE_DOCUMENTS permission may view image thumbnails for images it does not have permission to view. Version 3.17.1 contains a patch. There are no known workarounds.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: None
Availability: None

Exploit likelihood

0.95%Down 0.1 points since Jan 27, 2022

What each source reports

CVE List Score used 4.3

Permission bypass in Nextcloud Android App

Record: CVE-2021-41166
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-276
Updated: 2026-11-02

EUVDEUVD-2021-28274 4.3

Record: EUVD-2021-28274
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Updated: 2026-11-02

NVD 4.3

Record: CVE-2021-41166
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:P/I:N/A:N
Weakness: CWE-276
Updated: 2026-11-02

OSV 5.3

Record: CVE-2021-41166
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Updated: 2026-11-02

OSVBIT-nextcloud-2021-41166 No score

Permission bypass in Nextcloud Android App

Record: BIT-nextcloud-2021-41166
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`nextcloud` Bitnami	before 3.17.1	3.17.1

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-41166 is a medium vulnerability (CVSS 4.3) in Nextcloud, published January 26, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.95%, the 61st percentile. Fixed in nextcloud 3.17.1.