#VU66130 Input validation error in Nextcloud Server - CVE-2022-31120

Vulnerability identifier: #VU66130

Vulnerability risk: Low

CVSSv4.0: 0.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2022-31120

CWE-ID: CWE-20

Exploitation vector: Local network

Exploit availability: No

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

Vendor: Nextcloud

Description

The vulnerability allows a remote administrator on the local network to compromise the target system.

The vulnerability exists due to dederated share accepting/declining is not logged in audit log, leading to brute force attacks to go unnoticed

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Nextcloud Server: 22.2.0 - 23.0.3

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External links
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-9qvg-7fwg-722x
https://github.com/nextcloud/server/pull/31594/commits/1d8bf9a89c6856218802a1d365000a5831be8655
https://portal.nextcloud.com/article/using-the-audit-log-44.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

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