Vulnerability identifier: #VU83361

Vulnerability risk: Low

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

CVE-ID: CVE-2023-48304

CWE-ID: CWE-639

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 bypass authentication process.

The vulnerability exists due to the authorization bypass through user-controlled key. A remote user can enable and disable the birthday calendar for any user on the same server.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Nextcloud Enterprise Server: 22.0.0 - 27.0.2

Nextcloud Server: 25.0.0 - 27.0.2

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External links
http://github.com/nextcloud/security-advisories/security/advisories/GHSA-8jwv-c8c8-9fr3

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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.