Vulnerability identifier: #VU38928

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-0896

CWE-ID: CWE-862

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Zulip Server
Web applications / Other software

Vendor: Zulip

Description

The vulnerability allows a remote authenticated user to manipulate data.

Zulip Server 1.5.1 and below suffer from an error in the implementation of the invite_by_admins_only setting in the Zulip group chat application server that allowed an authenticated user to invite other users to join a Zulip organization even if the organization was configured to prevent this.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Zulip Server: 1.3.0 - 1.5.1

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External links
http://github.com/zulip/zulip/commit/1f48fa27672170bba3b9a97384905bb04c18761b
http://groups.google.com/forum/#!msg/zulip-announce/sUYeJv-fFmg/2TU2TLmNAwAJ
http://hackerone.com/reports/224210

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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.