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

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-30 · updated 2026-06-17
Weakness: CWE-79

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.

Affected products

Smoothwall Express: through 3.0; 3.1-update1, 3.1-update10, 3.1-update11, 3.1-update12, 3.1-update2, 3.1-update3 (+6)

References

https://community.smoothwall.org/forum/viewtopic.php?t=45095
https://www.vulncheck.com/advisories/smoothwall-express-reflected-xss-in-redirect-cgi-via-url-parameter

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