title: Nextcloud user scoped external storage can be used to gather credentials of other users
description: Nextcloud Server is a space for data storage on Nextcloud, a self-hosted productivity playform. In NextCloud Server versions 25.0.0 until 25.0.7 and 26.0.0 until 26.0.2 and Nextcloud Enterprise Server versions 19.0.0 until 19.0.13.9, 20.0.0 until 20.0.14.14, 21.0.0 until 21.0.9.12, 22.0.0 until 22.2.10.12, 23.0.0 until 23.0.12.7, 24.0.0 until 24.0.12.2, 25.0.0 until 25.0.7, and 26.0.0 until 26.0.2, a user could use this functionality to get access to the login credentials of another user and take over their account. This issue has been patched in Nextcloud Server versions 25.0.7 and 26.0.2 and NextCloud Enterprise Server versions 19.0.13.9, 20.0.14.14, 21.0.9.12, 22.2.10.12, 23.0.12.7, 24.0.12.2, 25.0.7, and 26.0.2.
Three workarounds are available. Disable app files_external. Change config setting "Allow users to mount external storage" to disabled in "Administration" > "External storage" settings `…/index.php/settings/admin/externalstorages`. Change config setting to disallow users to create external storages in "Administration" > "External storage" settings `…/index.php/settings/admin/externalstorages` with the types FTP, Nextcloud, SFTP, and/or WebDAV.
problem types: CWE-274: Improper Handling of Insufficient Privileges
affected:
{
vendor: nextcloud
product: security-advisories
versions:
version: Nextcloud Enterprise Server >= 19.0.0, < 19.0.13.9, status: affected
version: Nextcloud Enterprise Server >= 20.0.0.0, < 20.0.14.14, status: affected
version: Nextcloud Enterprise Server >= 21.0.0.0, < 21.0.9.12, status: affected
version: Nextcloud Enterprise Server >= 22.0.0.0, < 22.2.10.12, status: affected
version: Nextcloud Enterprise Server >= 23.0.0.0, < 23.0.12.7, status: affected
version: Nextcloud Enterprise Server >= 24.0.0.0, < 24.0.12.2, status: affected
version: Nextcloud Enterprise Server >= 25.0.0, < 25.0.7 , status: affected
version: Nextcloud Enterprise Server >= 26.0.0, < 26.0.2, status: affected
version: Nextcloud Server >= 25.0.0, < 25.0.7, status: affected
version: Nextcloud Server >= 26.0.0, < 26.0.2, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 8.5
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: HIGH
privilegesRequired: HIGH
scope: CHANGED
userInteraction: REQUIRED
vectorString: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
version: 3.1
]