XSS in Smoothwall Express
CVE-2026-27508
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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (16.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 16.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Smoothwall Express — versions 0
- Smoothwall Express — versions 3.1
Weakness classification (CWE)
References
- community.smoothwall.org/forum/viewtopic.php (Product, vendor-advisory, Release Notes, patch)
- www.vulncheck.com/advisories/smoothwall-express-reflected-xss-in-redirect-cgi-v… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-27508?
- CVE-2026-27508 is a medium-severity vulnerability in Smoothwall Express, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-03-30.
- How severe is CVE-2026-27508?
- Medium severity. CVSS v3 base score is 5.4 out of 10.