# CVE-2021-41241: Advanced permissions is not respected for subfolders in Nextcloud server

> Users can bypass advanced permission restrictions on subfolders in Nextcloud groupfolders by copying the folder, allowing unauthorized data access.

- **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:** 8 Mar 2022
- **Updated:** 23 Apr 2025
- **Also known as:** GHSA-m4wp-r357-4q94

## What is CVE-2021-41241?

CVE-2021-41241 is a medium-severity missing authorization vulnerability in Nextcloud Nextcloud Server, published on 8 Mar 2022. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Nextcloud server is a self hosted system designed to provide cloud style services. The groupfolders application for Nextcloud allows sharing a folder with a group of people. In addition, it allows setting "advanced permissions" on subfolders, for example, a user could be granted access to the groupfolder but not specific subfolders. Due to a lacking permission check in affected versions, a user could still access these subfolders by copying the groupfolder to another location. It is recommended that the Nextcloud Server is upgraded to 20.0.14, 21.0.6 or 22.2.1. Users unable to upgrade should disable the "groupfolders" application in the admin settings.

Weakness: CWE-862 (Missing Authorization), CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2021-41241?

It affects 1 product.


Products: Nextcloud Nextcloud Server.

## How do I fix CVE-2021-41241?

Upgrade to a fixed version.

## Is CVE-2021-41241 being exploited?

There is no known exploitation of CVE-2021-41241 in the wild and no public exploit code.

## Other vulnerabilities in Nextcloud Nextcloud Server

- [CVE-2021-32802](https://insights.sbomify.com/CVE-2021-32802/): Preview generation used third-party library not suited for user-generated content in Nextcloud server (critical 9.3)
- [CVE-2023-26482](https://insights.sbomify.com/CVE-2023-26482/): Scope of workflow operations is not validated in nextcloud server (critical 9.1)
- [CVE-2018-3775](https://insights.sbomify.com/CVE-2018-3775/): Auth bypass in Nextcloud Server (high 8.8)
- [CVE-2023-35172](https://insights.sbomify.com/CVE-2023-35172/): Nextcloud Server password reset endpoint is not brute force protected (high 8.7)
- [CVE-2023-32320](https://insights.sbomify.com/CVE-2023-32320/): Nextcloud Server's brute force protection allows someone to send more requests than intended (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41241 and fix it if it is affected.

What it is: CVE-2021-41241 is a medium-severity missing authorization vulnerability in Nextcloud Nextcloud Server, published on 8 Mar 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-2021-41241 in the wild and no public exploit code.

Affected product: Nextcloud Nextcloud Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2021-41241/ (Markdown: https://insights.sbomify.com/CVE-2021-41241/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41241
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41241
- OSV: https://osv.dev/vulnerability/CVE-2021-41241

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41241/
Summaries are generated and may contain mistakes; the official description above is the record.