Vulnerability identifier: #VU28978

Vulnerability risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-13964

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Roundcube
Web applications / Webmail solutions

Vendor: Roundcube

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks via the username template object.

The vulnerability exists due to insufficient sanitization of user-supplied data passed via the "username" template object in "include/rcmail_output_html.php". A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Roundcube: 1.3.0 - 1.3.11, 1.4.0 - 1.4.4

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External links
http://github.com/roundcube/roundcubemail/commit/37e2bc745723ef6322f0f785aefd0b9313a40f19
http://github.com/roundcube/roundcubemail/releases/tag/1.3.12
http://github.com/roundcube/roundcubemail/releases/tag/1.4.5
http://roundcube.net/news/2020/06/02/security-updates-1.4.5-and-1.3.12

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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.