Vulnerability identifier: #VU53718

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-2021-26092

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
FortiOS
Operating systems & Components / Operating system

Vendor: Fortinet, Inc

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in the SSL VPN web portal. A remote attacker can trick the victim to follow a specially crafted link to the error page 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 updates from vendor's website.

Vulnerable software versions

FortiOS: 6.4.0 - 6.4.5, 6.0.0 - 6.0.12, 6.2.0 - 6.2.7, 5.0.0 - 5.0.14, 5.6.0 - 5.6.13, 5.4.0 - 5.4.13, 5.2.0 - 5.2.15

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External links
http://www.fortiguard.com/psirt/FG-IR-20-199

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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.