What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-03-08 · updated 2026-06-17
• Weakness: CWE-863

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.

Affected products

• Nextcloud Server: before 20.0.14; from 21.0.0 before 21.0.6; 22.2.0 — fixed in 20.0.14, 21.0.6

How to fix

Upgrade to a fixed version: Nextcloud Server 20.0.14, 21.0.6. Check the vendor advisory for mitigations.

References

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

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