CVE-2021-40840
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 · uneditedA Stored XSS issue exists in the admin/users user administration form in LiveConfig 2.12.2.
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 confidenceA stored cross-site scripting (XSS) vulnerability exists in the admin/user management form of LiveConfig version 2.12.2. An attacker with admin access can inject malicious JavaScript code into user profile fields (such as name, email, or other input fields) which will be stored in the database and executed when other administrators view or manage users.
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= 2.12.2CVSS 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 installed LiveConfig versionRun 'liveconfig --version' or check the LiveConfig admin panel footer for the version numberAffected if Version is exactly 2.12.2
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Confirm admin interface is accessibleLog into the LiveConfig admin panel at the configured URL (typically port 7664) with administrative credentialsAffected if Admin access exists and the User Management interface is reachable
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Locate the User Management formNavigate to the admin panel, find the user management or admin/user management section where user profiles can be created or editedAffected if The user profile creation/editing form exists and accepts input in fields such as name or email
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Check for output encoding in user profile fieldsInspect the application behavior by creating a test user with HTML/JavaScript characters in the name or email field, then view that user in another admin session to see if the code executes or is rendered as plain textAffected if The application renders HTML/script tags without encoding when displaying user profile data to administrators
You are affected if your LiveConfig installation is version 2.12.2 and the admin user management form allows stored data to be rendered without sanitization, enabling script execution when administrators view user profiles.
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 output encoding for all user-supplied data in the admin user form. The application should sanitize or escape HTML/script tags before storing and before rendering user data in the administrative interface.
- 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-2021-40840 — 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-2021-40840 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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