Vulnerability identifier: #VU77663

Vulnerability risk: Medium

CVSSv3.1: 6.6 [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-35927

CWE-ID: CWE-284

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Nextcloud Enterprise Server
Client/Desktop applications / Messaging software
Nextcloud Server
Client/Desktop applications / Messaging software

Vendor: Nextcloud

Description

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

The vulnerability exists due to improper access restrictions when two servers are registered as trusted servers for each other and successfully exchanged the share secrets. A remote user can modify or delete VCards in the system addressbook on the origin server.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Nextcloud Enterprise Server: 16.0.0 - 26.0.1

Nextcloud Server: 25.0.0 - 26.0.1

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External links
http://github.com/nextcloud/security-advisories/security/advisories/GHSA-h7f7-535f-7q87

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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.