CVE-2026-26352: Smoothwall Express versions prior to 3.1 Update 13 contain a stored cross-site scripting vulnerability in the

Q: How do I fix CVE-2026-26352?

smoothwall express: upgrade to newer than 3.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-26352 being exploited?

CVE-2026-26352 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-26352 affect?

CVE-2026-26352 affects smoothwall express. Severity is medium (CVSS 5.4). 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 JavaS

Q: How urgent is CVE-2026-26352?

Priority 20/100. No elevated risk signals yet.

Routine

MEDIUM 5.4UPGRADE

CVE-2026-26352 is a medium-severity flaw (CVSS 5.4) affecting smoothwall express. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.1% (top 96%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-03-30
Last modified	2026-06-17

Publisher (CNA): VulnCheck · Vendor: smoothwall

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-30 17:16 UTCPublished CVE record published
2026-06-17 10:26 UTCUpdated Record last modified

smoothwall smoothwall express UPGRADE

Affected: <= 3.0 · 3.1 update1 · 3.1 update10 · 3.1 update11 · 3.1 update12 · 3.1 update2 · 3.1 update3 · 3.1 update4

Fixed in: newer than 3.0

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-26352?

smoothwall express: upgrade to newer than 3.0. Exact commands for each OS are on this page.

Is CVE-2026-26352 being exploited?

CVE-2026-26352 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-26352 affect?

CVE-2026-26352 affects smoothwall express. Severity is medium (CVSS 5.4). 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 JavaS

How urgent is CVE-2026-26352?

Priority 20/100. No elevated risk signals yet.

Related CVEs

CVE-2026-27508 MEDIUM 5.4 UPGRADE Smoothwall Express versions prior to 3.1 Update 13 contain a reflected cross-site scripting vulnerability in t
CVE-2019-25395 HIGH 7.2 MITIGATE Smoothwall Express 3.1-SP4-polar-x86_64-update9 contains multiple stored cross-site scripting vulnerabilities
CVE-2019-25394 HIGH 7.2 MITIGATE Smoothwall Express 3.1-SP4-polar-x86_64-update9 contains multiple stored cross-site scripting vulnerabilities
CVE-2019-25393 MEDIUM 6.1 MITIGATE Smoothwall Express 3.1-SP4-polar-x86_64-update9 contains a reflected cross-site scripting vulnerability that a
CVE-2019-25392 MEDIUM 6.1 MITIGATE Smoothwall Express 3.1-SP4-polar-x86_64-update9 contains a reflected cross-site scripting vulnerability that a

References

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