CVE-2026-34819
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedEndian Firewall version 3.3.25 and prior allow stored cross-site scripting (XSS) via the REMARK parameter to /cgi-bin/openvpnclient.cgi. An authenticated attacker can inject arbitrary JavaScript that is stored and executed when other users view the affected page.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceEndian Firewall versions 3.3.25 and prior contain a stored XSS vulnerability in the /cgi-bin/openvpnclient.cgi endpoint. The REMARK parameter is not properly sanitized, allowing authenticated attackers to inject malicious JavaScript that persists and executes when other users access the affected page.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 3.3.25CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check Endian Firewall versionAccess the admin web interface and navigate to Status > System or check /etc/redhat-release, /etc/efw/version to find the installed version numberAffected if Installed version is 3.3.25 or lower (Community edition)
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Verify OpenVPN client CGI existsCheck if the file openvpnclient.cgi exists in the web CGI directory, typically under /var/www/cgi-bin/ or /usr/local/easywrt/htdocs/cgi-bin/Affected if The openvpnclient.cgi file exists on the system
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Confirm OpenVPN client feature is enabledLog into the admin interface and check if the OpenVPN Client feature is configured under VPN > OpenVPN Client, or check configuration files in /var/efw/openvpn/ for client configurationsAffected if OpenVPN client functionality is enabled and configured
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Inspect REMARK parameter storageCheck the configuration or database where OpenVPN client remarks are stored, typically in /var/efw/openvpn/config or the web application database, for unsanitized input in the REMARK fieldAffected if The REMARK field accepts and stores raw user input without sanitization visible in the stored configuration
A user is affected if they are running Endian Firewall Community version 3.3.25 or lower with the OpenVPN client feature enabled and the openvpnclient.cgi script present, where the REMARK parameter can be injected with script content.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement proper input validation and context-aware output encoding for the REMARK parameter in openvpnclient.cgi to neutralize malicious script content before storage and before display to users.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-34819 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-34819 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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