CVE-2011-2188
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 · uneditedLuaExpat before 1.2.0 does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.
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 confidenceLuaExpat before 1.2.0 is a Lua XML parsing library that fails to detect or limit recursion during XML entity expansion. Attackers can exploit this by sending crafted XML documents with deeply nested entity references (similar to the 'Billion Laughs' attack), causing excessive memory and CPU consumption leading to denial of service.
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<= 1.1.0= 1.0= 1.0.1= 1.0.2CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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 LuaExpat versionRun 'luarocks show luaexpat' or check the installed package version via your Lua package manager (luarocks). Alternatively, inspect the source file 'lxp.lua' or 'lxp.h' in the LuaExpat library directory for the version string.Affected if The installed version is 1.1.0 or earlier, or specifically 1.0, 1.0.1, or 1.0.2.
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Verify XML parsing is in useSearch your application codebase for require('lxp') or lxp.new() calls, which indicate LuaExpat is being used to parse XML documents.Affected if Your application loads and uses the LuaExpat library to parse XML.
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Confirm entity expansion is enabledCheck the lxp parser configuration. By default, LuaExpat parses external entities when the 'Entity' or 'ExternalEntity' callbacks are registered, or when the XML input contains DOCTYPE declarations with ENTITY definitions.Affected if Your application parses XML documents that may contain DOCTYPE declarations with entity definitions, or processes untrusted XML input.
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Assess input trust levelReview whether XML data comes from untrusted sources (user uploads, external APIs, network requests). If the parser handles any XML not generated internally by a trusted system, it may be vulnerable.Affected if The application processes XML from untrusted or external sources without pre-validation.
You are affected if LuaExpat version 1.1.0 or earlier is installed AND your application parses XML with entity definitions from any untrusted source.
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 LuaExpat version 1.2.0 or later which implements proper entity expansion recursion limits. If immediate upgrade is not feasible, implement input validation to reject XML documents with excessive entity nesting before passing to the parser.
- Consultation1.0 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 $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-2188 — 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-2011-2188 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
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