CVE-2026-34803
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 name parameter to /manage/qos/classes/. 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 3.3.25 and prior contains a stored cross-site scripting (XSS) vulnerability in the QoS classes management interface (/manage/qos/classes/). The 'name' parameter does not properly sanitize user input, allowing an authenticated attacker to inject arbitrary JavaScript code that persists on the page and executes in the browsers of other users who view the affected functionality.
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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Identify Endian Firewall versionAccess the admin interface or check system information to determine the installed Endian Firewall Community version. This is typically visible in the dashboard or system settings.Affected if The installed version is 3.3.25 or any prior version.
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Confirm QoS module is accessibleVerify that the /manage/qos/classes/ endpoint is reachable in the admin interface by attempting to access it while authenticated.Affected if The endpoint is accessible and the QoS feature is enabled in the firewall configuration.
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Check for existing XSS payloads in QoS class namesNavigate to the QoS classes management page at /manage/qos/classes/ and inspect the list of configured class names for any suspicious JavaScript code or unusual characters that may indicate injected payloads.Affected if Any QoS class name contains unsanitized HTML or JavaScript code such as <script> tags, event handlers, or encoded payloads.
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Review user permissions for QoS managementCheck which authenticated users have access to the QoS classes management interface and review audit logs for any recent changes to QoS class configurations.Affected if Multiple user accounts have write access to QoS classes and there are unexpected modification records.
A system is affected if it runs Endian Firewall Community version 3.3.25 or earlier, has the QoS feature enabled with the /manage/qos/classes/ endpoint accessible, and contains any QoS class names with potentially malicious injected 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 dataApply any available vendor patch for Endian Firewall; in the interim, implement output encoding for the name parameter and add input validation/sanitization to prevent injection of script content.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,848.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-34803 — 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-2026-34803 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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