CVE-2006-1821
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 · uneditedDirectory traversal vulnerability in index.php in ModX 0.9.1 allows remote attackers to read arbitrary files via a .. (dot dot) sequence and trailing NULL (%00) byte in the id parameter.
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 confidenceModX 0.9.1 contains a directory traversal vulnerability in index.php where the id parameter accepts '..' sequences and trailing NULL bytes (%00), allowing remote attackers to read arbitrary files on the server filesystem.
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= 0.9.1CVSS 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
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- None
AV:N/AC:L/Au:N/C:P/I:P/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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Confirm ModX versionLocate and inspect version files or headers in the ModX installation directory. Check files such as version.php, core/docs/changelog.txt, or the admin dashboard for the installed version number.Affected if The installed version is ModX 0.9.1 specifically.
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Verify index.php exists and is web-accessibleConfirm that index.php from the ModX 0.9.1 installation is present in the web root and accessible via HTTP/HTTPS.Affected if index.php is present and serves as the entry point for the application.
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Inspect the id parameter handling in index.phpReview the source code of index.php to locate how the 'id' parameter is processed. Search for code that uses $_GET['id'] or $_REQUEST['id'] and passes it to file inclusion or file reading functions.Affected if The 'id' parameter is used in file operations (such as include, require, file_get_contents, fopen) without proper sanitization.
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Check for path traversal vulnerability in id parameter processingExamine the code around the 'id' parameter usage to determine if it validates against '..' sequences or strips/stops at null bytes (%00). Look for functions like basename(), realpath(), or explicit checks for '..'Affected if The code does NOT validate the id parameter against directory traversal sequences (does not reject or sanitize '..') and does NOT properly handle null bytes.
A system is affected if it runs ModX version 0.9.1 with the vulnerable index.php file accessible and the id parameter processed without sanitizing '..' sequences and null bytes.
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 to a patched version of ModX that addresses this vulnerability, or implement input validation in index.php to reject path traversal sequences and strip/nullify null bytes from the id parameter.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2006-1821 — 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-2006-1821 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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