XSS in Smoothwall Express
CVE-2026-26352
Smoothwall Express versions prior to 3.1 Update 13 contain a stored cross-site scripting vulnerability in the /cgi-bin/vpnmain.cgi script due to improper sanitation of the VPN_IP parameter. Authenticated attackers can inject arbitrary JavaScript through VPN configuration settings that executes when the affected page is viewed by other users.
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:L/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (13.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 13.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · 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-stored-xss-in-vpnmain-cgi-via-v… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-26352?
- CVE-2026-26352 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-2026-26352?
- Medium severity. CVSS v3 base score is 5.4 out of 10.