CVE-2023-39543
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 · uneditedCross-site scripting vulnerability in LuxCal Web Calendar prior to 5.2.3M (MySQL version) and LuxCal Web Calendar prior to 5.2.3L (SQLite version) allows a remote unauthenticated attacker to execute an arbitrary script on the web browser of the user who is using the product.
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 confidenceCross-site scripting (XSS) vulnerability in LuxCal Web Calendar versions prior to 5.2.3M (MySQL) and 5.2.3L (SQLite) allows remote unauthenticated attackers to inject malicious scripts into web pages viewed by users, potentially stealing session cookies or performing actions on behalf of authenticated 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< 5.2.3m< 5.2.3lCVSS 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
- None
CVSS:3.1/AV:N/AC:L/PR:N/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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Locate LuxCal Web Calendar installationSearch your web server directories for the LuxCal calendar files. Check for a folder named 'luxcal' or similar. Look for a file named 'index.php' or 'calendar.php' that displays the LuxCal branding.Affected if LuxCal Web Calendar is found on the server
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Identify installed LuxCal versionOpen the file 'common/lyxcaldefs.php' or 'inc/lyxcaldefs.php' in the LuxCal directory. Look for a line defining a version constant (such as $LxCalV or define('LXCAL_VERSION', ...)). Note the exact version number displayed.Affected if Version is below 5.2.3M (for MySQL) or below 5.2.3L (for SQLite)
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Determine database type in useCheck the LuxCal configuration file (usually 'config.php' or found in a 'database' folder). Look for database connection settings. If you see MySQL or mysqli connection parameters, the MySQL version applies. If you see SQLite or a .db file path, the SQLite version applies.Affected if Using MySQL version with build less than M, or SQLite version with build less than L
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Confirm web exposureVerify that the LuxCal calendar is accessible over HTTP/HTTPS to unauthenticated users. Try accessing the main calendar URL without logging in. The vulnerability is exploitable by remote unauthenticated attackers.Affected if Calendar is publicly accessible without authentication
You are affected if LuxCal Web Calendar is installed and the version is below 5.2.3M (MySQL) or below 5.2.3L (SQLite) and is accessible to unauthenticated users.
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.
dbcve · scoped5.2.3m5.2.3l
Upgrade to LuxCal Web Calendar version 5.2.3M (MySQL) or 5.2.3L (SQLite) or later. Until patched, users should avoid clicking suspicious links and administrators should implement Content Security Policy (CSP) headers as a defense-in-depth measure.
5.2.3M for MySQL variant, 5.2.3L for SQLite variant
- Backup your existing LuxCal Web Calendar installation and database before proceeding
- Determine which database backend your installation uses (MySQL or SQLite)
- Download LuxCal Web Calendar version 5.2.3M (for MySQL) or version 5.2.3L (for SQLite) from the official vendor website (www.luxsoft.eu)
- Replace the existing LuxCal files with the files from the new version, preserving your configuration and database
- Verify the calendar functions correctly after the upgrade
- Confirm the XSS vulnerability is no longer present
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-39543 — 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-2023-39543 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