#VU35691 Cross-site scripting in gnuboard5 - CVE-2018-18671

Vulnerability identifier: #VU35691

Vulnerability risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-18671

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
gnuboard5
Web applications / Forum & blogging software

Vendor: SIR

Description

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

The vulnerability exists due to insufficient sanitization of user-supplied data when processing the "mobile board head contents" parameter, aka the adm/board_form_update.php bo_mobile_content_head parameter. 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

gnuboard5: 5.3.1.9

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External links
https://github.com/gnuboard/gnuboard5/commit/a45241f4bc46aee1ab2cc0749f6444b043681edf#diff-05e83ad5f4c0624ed6ff385aed1bf33b
https://github.com/gnuboard/gnuboard5/compare/15b2e73...2549172
https://github.com/gnuboard/gnuboard5/releases/tag/5.3.2.0

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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.