CVE-2026-27404
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 · uneditedUnauthenticated Cross Site Scripting (XSS) in LMS <= 9.7 versions.
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 confidenceUnauthenticated Cross-Site Scripting (XSS) vulnerability in Learning Management System (LMS) versions 9.7 and below allows remote attackers to inject malicious JavaScript or HTML through unsanitized user input without requiring authentication.
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
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
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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Confirm LMS installation and identify the productLocate the Learning Management System in your environment. Identify the vendor/product name, installation directory, and any web server configurations pointing to the LMS application.Affected if The system is running a Learning Management System without knowing the vendor or version
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Determine the installed LMS versionCheck the LMS version by reviewing the application itself (typically visible in the footer, admin panel, or 'About' section), or by examining version files in the installation directory (common locations: /version, /VERSION, /config/version.php, or a package.json/Changelog file).Affected if The installed version is 9.7 or lower, or the version cannot be determined and the product claims to be an LMS
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Identify accessible user input pointsReview the LMS web interface for unauthenticated input forms such as login fields, registration forms, search boxes, profile fields, or public submission forms. Check if these endpoints are reachable without authentication.Affected if Unauthenticated user input forms are accessible on the LMS web interface
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Verify if input sanitization is presentTest the identified input fields by submitting a benign test string containing special characters (e.g., <script>alert(1)</script>) and observe if the output is reflected as-is or properly encoded. Alternatively, review the application's source code for input validation functions.Affected if User input is reflected back in the response without HTML encoding or sanitization, indicating the vulnerability is present and exploitable
The environment is affected if a Learning Management System is installed with version 9.7 or lower and has unauthenticated input fields that reflect unsanitized user input back to the browser.
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 dataUpgrade LMS to a version newer than 9.7 or apply vendor-supplied security patches; implement input validation and output encoding as defense-in-depth while awaiting the update.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-27404 — 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-2026-27404 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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