Vulnerability identifier: #VU50774

Vulnerability risk: Low

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

CVE-ID: N/A

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

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

Vendor: Mattermost, Inc.

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to insufficient validation of user-supplied input in image proxy component for URLs. A remote attacker can bypass implemented security restrictions.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mattermost Server: 5.0.0 - 5.30.3

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External links
http://mattermost.com/security-updates/#MMSA-2020-0039

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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.