CVE-2026-27508 Smoothwall Express < 3.1 Update 13 Reflected XSS in redirect.cgi via url Parameter

What is CVE-2026-27508?

CVE-2026-27508 is a medium-severity cross-site scripting vulnerability in Smoothwall Express, published on 30 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Smoothwall Express versions prior to 3.1 Update 13 contain a reflected cross-site scripting vulnerability in the /redirect.cgi endpoint due to improper sanitation of the url parameter. Attackers can craft malicious URLs with javascript: schemes that execute arbitrary JavaScript in victims' browsers when clicked through the unsanitized link.

Weakness: CWE-79

Which versions are affected by CVE-2026-27508?

It affects 1 product.

Products include Smoothwall Smoothwall Express.

How do I fix CVE-2026-27508?

No fix has been published for CVE-2026-27508 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-27508 being exploited?

There is no known exploitation of CVE-2026-27508 in the wild and no public exploit code.

Other vulnerabilities in Smoothwall Express

• CVE-2011-1085 Cross-site request forgery in Smoothwall Express High 8.8
• CVE-2011-1084 Cross-site scripting in Smoothwall Express Medium 6.1
• CVE-2019-25379 Smoothwall Express 3.1 'urlfilter.cgi' Cross-Site Scripting Medium 5.3
• CVE-2019-25394 Smoothwall Express 3.1 'modem.cgi' Cross-Site Scripting Medium 5.3
• CVE-2019-25395 Smoothwall Express 3.1 'preferences.cgi' Cross-Site Scripting Medium 5.3

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-rx2c-j693-rp5c.