# CVE-2021-41166: Permission bypass in Nextcloud Android App

> An unauthorized app can view image thumbnails without required permissions, leading to sensitive information disclosure in the Nextcloud Android client.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jan 2022
- **Updated:** 23 Apr 2025
- **Also known as:** BIT-nextcloud-2021-41166, GHSA-wrwg-jwpg-r3c4

## What is CVE-2021-41166?

CVE-2021-41166 is a medium-severity missing authorization vulnerability in nextcloud security-advisories, published on 26 Jan 2022. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-276 (Incorrect Default Permissions)

## Which versions are affected by CVE-2021-41166?

1 open source package ship an affected version, including nextcloud. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nextcloud` | Bitnami | All versions | 3.17.1 |

Products: Nextcloud Nextcloud.

## How do I fix CVE-2021-41166?

Upgrade nextcloud to 3.17.1 or later.

## Is CVE-2021-41166 being exploited?

There is no known exploitation of CVE-2021-41166 in the wild and no public exploit code.

## Other vulnerabilities in nextcloud security-advisories

- [CVE-2019-5454](https://insights.sbomify.com/CVE-2019-5454/): SQL injection in com.nextcloud.client (critical 9.8)
- [CVE-2021-43863](https://insights.sbomify.com/CVE-2021-43863/): SQL Injection in FileContentProvider (GHSL-2021-1007) (high 7.5)
- [CVE-2019-5450](https://insights.sbomify.com/CVE-2019-5450/): Cross-site scripting in com.nextcloud.client (medium 6.8)
- [CVE-2019-5455](https://insights.sbomify.com/CVE-2019-5455/): Auth bypass in com.nextcloud.client (medium 6.8)
- [CVE-2021-22905](https://insights.sbomify.com/CVE-2021-22905/): Information disclosure in Nextcloud Android App (com.nextcloud.client) (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41166 and fix it if it is affected.

What it is: CVE-2021-41166 is a medium-severity missing authorization vulnerability in nextcloud security-advisories, published on 26 Jan 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-41166 in the wild and no public exploit code.

Affected packages and fixed versions:
- nextcloud (Bitnami): affected all versions; fixed in 3.17.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-41166/ (Markdown: https://insights.sbomify.com/CVE-2021-41166/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41166
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41166
- OSV: https://osv.dev/vulnerability/CVE-2021-41166

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41166/
Summaries are generated and may contain mistakes; the official description above is the record.