What is CVE-2021-41241?

CVE-2021-41241 is a medium-severity vulnerability in Nextcloud Server, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2022-03-08.

How severe is CVE-2021-41241?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Is CVE-2021-41241 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Auth bypass in Nextcloud Server

CVE-2021-41241

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.

Vulnerability class: Broken Access Control

Published 2022-03-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.009 (56.5th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 56.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Nextcloud Server — versions 22.2.0
Nextcloud Security-Advisories — versions < 20.0.14, >= 21.0.0, < 21.0.6, >= 22.2.0, < 22.2.1

Weakness classification (CWE)

Public proof-of-concept exploits

References

github.com/nextcloud/security-advisories/security/advisories/GHSA-m4wp-r357-4q94 (Third Party Advisory, Issue Tracking)
github.com/nextcloud/groupfolders/issues/1692 (Patch, Third Party Advisory, Issue Tracking)
github.com/nextcloud/server/pull/29362 (Patch, Third Party Advisory)
security.gentoo.org/glsa/202208-17 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2021-41241?: CVE-2021-41241 is a medium-severity vulnerability in Nextcloud Server, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2022-03-08.
How severe is CVE-2021-41241?: Medium severity. CVSS v3 base score is 4.3 out of 10.
Is CVE-2021-41241 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.