CVE-2026-14449
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 · uneditedu5CMS through v12.8.8 is vulnerable to reflected XSS via the ‘thanks’ parameter in multiple form components
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 · moderate confidenceu5CMS through v12.8.8 contains a reflected cross-site scripting (XSS) vulnerability in the 'thanks' parameter across multiple form components. The vulnerability allows attackers to inject malicious JavaScript through the unsanitized 'thanks' parameter, which is reflected back to users in the application's response.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- None
- Authentication
- X
- User interaction
- A
- Scope
- X
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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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Determine the installed u5CMS versionCheck the version file, header, or admin interface of your u5CMS installation. Common locations include a version.php file, CHANGELOG, or the admin dashboard.Affected if The version is v12.8.8 or any earlier version (u5CMS through v12.8.8)
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Identify form components using the thanks parameterSearch the codebase for occurrences of the 'thanks' parameter in form handling code. Look for $_GET, $_POST, or $_REQUEST usage of 'thanks' in PHP files within the form handling directories.Affected if The application uses form components that accept and process a 'thanks' parameter from user input
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Verify the thanks parameter is reflected without sanitizationSubmit a test request to a form that accepts the 'thanks' parameter with a benign payload such as thanks=<script>alert(1)</script> and observe if the payload is reflected unchanged in the response.Affected if The 'thanks' parameter value is reflected directly in the HTML response without encoding or validation
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Check multiple form endpoints for the vulnerabilityTest different form components in the application that may use the 'thanks' parameter, such as contact forms, feedback forms, or registration forms.Affected if Any form component reflects the unsanitized 'thanks' parameter back to the user
If the installed u5CMS version is v12.8.8 or earlier AND the application uses any form component that accepts a 'thanks' parameter which gets reflected without sanitization, the environment is affected by this reflected XSS vulnerability.
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 strict input validation and output encoding on the 'thanks' parameter in all form components. Consider upgrading to a patched version if available.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-14449 — 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-2026-14449 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
- No spam, self-promotion, credentials, or personal data