Advanced permissions is not respected for subfolders in Nextcloud server
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-863.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| nextcloud | security-advisories | before 20.0.14; 21.0.0 to before 21.0.6; 22.2.0 to before 22.2.1 | 20.0.14, 21.0.6, 22.2.1 | Patch available | CNA |
- security-advisories Vendornextcloud Affected before 20.0.14; 21.0.0 to before 21.0.6; 22.2.0 to before 22.2.1 Fixed in 20.0.14, 21.0.6, 22.2.1 Patch available CNA
Remediation
- Fix · CNA security-advisories (nextcloud) Fixed in 20.0.14, 21.0.6, 22.2.1
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-41241
References
More Nextcloud Server vulnerabilities
- TI-2023-20855 Users can delete external storage mount points CVSS 3.1HIGH 7.7
- TI-2023-11091 Nextcloud download permissions can be changed by resharer CVSS 3.1HIGH 7.5
- TI-2023-10624 Nextcloud Server vulnerable to SSRF via filter bypass due to lax checking on IPs CVSS 3.1MEDIUM 5.3
- TI-2025-37238 Cross-site scripting in Nextcloud CVSS 3.1MEDIUM 6.4
- TI-2023-11086 nextcloud vulnerable to Uncontrolled Resource Consumption CVSS 3.1MEDIUM 6.5
- TI-2022-18738 Exception logging in Sharepoint app reveals clear-text connection details CVSS 3.1MEDIUM 6.5
Sources
- CVE-2021-41241 · CVE Program
- CVE-2021-41241 · NVD
- FIRST EPSS
- CVE-2021-41241 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences