title: Nextcloud Desktop client misbehaves with E2EE when the server returns empty list of metadata keys
description: The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server. Starting with version 3.0.0 and prior to version 3.6.5, a malicious server administrator can gain full access to an end-to-end encrypted folder. They can decrypt files, recover the folder structure, and add new files.​ Users should upgrade the Nextcloud Desktop client to 3.6.5 to receive a patch. No known workarounds are available.
problem types: CWE-325: Missing Cryptographic Step
affected:
{
vendor: nextcloud
product: security-advisories
versions:
version: >= 3.0.0, < 3.6.5, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: PHYSICAL
availabilityImpact: NONE
baseScore: 6.7
baseSeverity: MEDIUM
confidentialityImpact: HIGH
integrityImpact: HIGH
privilegesRequired: HIGH
scope: CHANGED
userInteraction: REQUIRED
vectorString: CVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
version: 3.1
]