CVE-2021-32766 Nextcloud Text app can disclose existence of folders in "File Drop" link share

Medium 5.3 Published 7 Sep 2021 Updated 3 Aug 2024

Attackers with valid File Drop links can enumerate folder existence in Nextcloud Text shares, leaking directory structure information.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2021-32766?

CVE-2021-32766 is a medium-severity vulnerability in Nextcloud Nextcloud Server, published on 7 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Nextcloud Text is an open source plaintext editing application which ships with the nextcloud server. In affected versions the Nextcloud Text application returned different error messages depending on whether a folder existed in a public link share. This is problematic in case the public link share has been created with "Upload Only" privileges. (aka "File Drop"). A link share recipient is not expected to see which folders or files exist in a "File Drop" share. Using this vulnerability an attacker is able to enumerate folders in such a share. Exploitation requires that the attacker has access to a valid affected "File Drop" link share. It is recommended that the Nextcloud Server is upgraded to 20.0.12, 21.0.4 or 22.0.1. Users who are unable to upgrade are advised to disable the Nextcloud Text application in the app settings.

Weakness: CWE-209

Which versions are affected by CVE-2021-32766?

It affects 1 product.

Products include Nextcloud Nextcloud Server.

How do I fix CVE-2021-32766?

Upgrade to a fixed version.

Is CVE-2021-32766 being exploited?

There is no known exploitation of CVE-2021-32766 in the wild and no public exploit code.

All Nextcloud Nextcloud Server vulnerabilities

Sources

Also known as GHSA-gcf3-3wmc-88jr.