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.
The product generates an error message that includes sensitive information about its environment, users, or associated data.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Nextcloud_server | Nextcloud | * | 20.0.12 (excluding) |
| Nextcloud_server | Nextcloud | 21.0.0 (including) | 21.0.4 (excluding) |
| Nextcloud_server | Nextcloud | 22.0.0 (including) | 22.1.0 (excluding) |
The sensitive information may be valuable information on its own (such as a password), or it may be useful for launching other, more serious attacks. The error message may be created in different ways:
An attacker may use the contents of error messages to help launch another, more focused attack. For example, an attempt to exploit a path traversal weakness (CWE-22) might yield the full pathname of the installed application. In turn, this could be used to select the proper number of “..” sequences to navigate to the targeted file. An attack using SQL injection (CWE-89) might not initially succeed, but an error message could reveal the malformed query, which would expose query logic and possibly even passwords or other sensitive information used within the query.