CVE-2021-32688 Information

Description

Nextcloud Server is a Nextcloud package that handles data storage. Nextcloud Server supports application specific tokens for authentication purposes. These tokens are supposed to be granted to a specific applications (e.g. DAV sync clients) and can also be configured by the user to not have any filesystem access. Due to a lacking permission check the tokens were able to change their own permissions in versions prior to 19.0.13 20.0.11 and 21.0.3. Thus fileystem limited tokens were able to grant themselves access to the filesystem. The issue is patched in versions 19.0.13 20.0.11 and 21.0.3. There are no known workarounds aside from upgrading.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Reference

https://hackerone.com/reports/1193321 https://github.com/nextcloud/security-advisories/security/advisories/GHSA-48m7-7r2r-838r https://github.com/nextcloud/server/pull/27000 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/J63NBVPR2AQCAWRNDOZSGRY5II4WS2CZ/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BVZS26RDME2DYTKET5AECRIZDFUGR2AZ/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.8