CVE-2026-26352Network attack vector

Stored XSS via unsanitized VPN_IP configuration

Published Mar 30, 2026 · Updated Mar 30, 2026

Stored XSS in Smoothwall Express before 3.1 Update 13 allows remote authenticated users to execute JavaScript in other users' browsers. The /cgi-bin/vpnmain.cgi script stores the VPN_IP configuration value without proper sanitization and later renders it into the VPN page. The attacker needs authenticated access to change VPN settings, and execution occurs only when another user views the affected page.

CVSS severity5.1
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Smoothwall Express before 3.1 Update 13 allows remote authenticated users to execute JavaScript in other users' browsers. The /cgi-bin/vpnmain.cgi script stores the VPN_IP configuration value without proper sanitization and later renders it into the VPN page. The attacker needs authenticated access to change VPN settings, and execution occurs only when another user views the affected page.

The record

CVE
CVE-2026-26352
Published
Mar 30, 2026
Updated
Mar 30, 2026
Vendor
Smoothwall
Product
Smoothwall Express
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=3.1 Update 13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Smoothwall · Smoothwall Expressversion=0 <=3.1 Update 13

Published CVSS scores

5.4VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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