Vulnerability identifier: #VU34232

Vulnerability risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-20866

CWE-ID: CWE-444

Exploitation vector: Network

Exploit availability: No

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

Vendor: Mattermost, Inc.

Description

The vulnerability allows a remote non-authenticated attacker to gain access to sensitive information.

An issue was discovered in Mattermost Server before 5.12.0. Use of a Proxy HTTP header, rather than the source address in an IP packet header, for obtaining IP address information was mishandled.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Mattermost Server: 5.0.0 - 5.11.1

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External links
http://mattermost.com/security-updates/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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