Multiple vulnerabilities in Nextcloud Server

Published: 2023-04-07

Risk	Low
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2023-28834 CVE-2023-28844
CWE-ID	CWE-200 CWE-284
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	Nextcloud Server Client/Desktop applications / Messaging software Nextcloud Enterprise Server Client/Desktop applications / Messaging software
Vendor	Nextcloud

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Information disclosure

EUVDB-ID: #VU74599

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-28834

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a remote user to gain access to potentially sensitive information.

The vulnerability exists due to excessive data output by the application. A remote user can obtain the full data directory path of the Nextcloud server from an API endpoint.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Nextcloud Server: 23.0.0 - 25.0.5

Nextcloud Enterprise Server: 23.0.0 - 25.0.3

External links

http://github.com/nextcloud/server/issues/33883
http://hackerone.com/reports/1690510
http://github.com/nextcloud/server/pull/36094
http://github.com/nextcloud/security-advisories/security/advisories/GHSA-5w64-6c42-rgcv

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Improper access control

EUVDB-ID: #VU74598

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-28844

CWE-ID: CWE-284 - Improper Access Control

Exploit availability: No

Description

The vulnerability allows a remote user to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions. A remote user without download permissions can bypass implemented security restrictions and download older versions of files from the server.