Reflected XSS via unsanitized redirect URL
Published Mar 30, 2026 · Updated Mar 30, 2026
Reflected XSS in Smoothwall Express before 3.1 Update 13 allows remote attackers to execute JavaScript via a crafted URL. The /redirect.cgi endpoint places the url parameter into a link without rejecting the javascript: scheme, causing browsers to treat the value as script. Exploitation requires a victim to click the malicious link; the script runs in that victim's browser and can read or alter data available to the page.
Summary
What happened
Reflected XSS in Smoothwall Express before 3.1 Update 13 allows remote attackers to execute JavaScript via a crafted URL. The /redirect.cgi endpoint places the url parameter into a link without rejecting the javascript: scheme, causing browsers to treat the value as script. Exploitation requires a victim to click the malicious link; the script runs in that victim's browser and can read or alter data available to the page.
The record
- CVE
- CVE-2026-27508
- Published
- Mar 30, 2026
- Updated
- Mar 30, 2026
- Vendor
- Smoothwall
- Product
- Smoothwall Express
- Classifications
- CWE-79, T1189
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 30, 2026CVE publishedPublication date reported by the CVE source.
- 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.
- Affected versionversion=0 <=3.1 Update 13
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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