CVE-2021-41179: Two-Factor Authentication not enforced for pages marked as public
Nextcloud is an open-source, self-hosted productivity platform. Prior to Nextcloud Server versions 20.0.13, 21.0.5, and 22.2.0, the Two-Factor Authentication wasn't enforced for pages marked as public. Any page marked as @PublicPage could thus be accessed with a valid user session that isn't authenticated. This particularly affects the Nextcloud Talk application, as this could be leveraged to gain access to any private chat channel without going through the Two-Factor flow. It is recommended that the Nextcloud Server be upgraded to 20.0.13, 21.0.5 or 22.2.0. There are no known workarounds aside from upgrading.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is Nextcloud?
Nextcloud is an open-source, self-hosted productivity platform.
What versions of Nextcloud Server are affected by CVE-2021-41179?
Nextcloud Server versions 20.0.3 to 20.0.13, 21.0.1 to 21.0.5, and 22.1.1 to 22.2.0 are affected.
What is the severity of CVE-2021-41179?
The severity of CVE-2021-41179 is medium with a CVSS score of 6.5.
How can an attacker exploit CVE-2021-41179?
An attacker can exploit CVE-2021-41179 by accessing pages marked as `@PublicPage` without proper authentication through Two-Factor Authentication.
Are there any mitigations available for CVE-2021-41179?
Yes, upgrading to Nextcloud Server versions 20.0.13, 21.0.5, or 22.2.0 or later fixes the vulnerability.