CVE-2024-3884
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 flaw was found in Undertow that can cause remote denial of service attacks. When the server uses the FormEncodedDataDefinition.doParse(StreamSourceChannel) method to parse large form data encoding with application/x-www-form-urlencoded, the method will cause an OutOfMemory issue. This flaw allows unauthorized users to cause a remote denial of service (DoS) attack.
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 confidenceA denial of service vulnerability exists in Undertow's FormEncodedDataDefinition.doParse() method. When parsing large form data with application/x-www-form-urlencoded content type, the method loads the entire request body into memory without proper bounds checking, causing an OutOfMemoryError that crashes the server.
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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 Undertow installationLocate the undertow-core JAR file in your application (search in lib/, WEB-INF/lib/, or application server modules directory) or check your build manifest/pom for undertow dependency versionAffected if Undertow is present in the environment and its version falls within the affected range (prior to fix)
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Determine Undertow versionExtract or inspect the undertow-core version from the JAR manifest, pom.xml, or list the installed packages if using an application server package (e.g., rpm -qi undertow-core or similar)Affected if The installed version is unknown or older than the patched version - compare against the official CVE advisory for version numbers
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Verify form parsing is in useInspect your web application endpoints and Undertow server configuration for handlers that process application/x-www-form-urlencoded requests (HTML forms, API endpoints accepting form data)Affected if Your application accepts or processes URL-encoded form submissions through Undertow's FormEncodedDataDefinition
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Check request body configurationExamine undertow-server.xml, jboss-web.xml, or the Undertow builder configuration for any existing http-handler or server builder settings that explicitly limit max-request-body-sizeAffected if No explicit request body size limits are configured and the Undertow version is unpatched or within the vulnerable range
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Confirm exposed attack surfaceReview access logs or API gateway logs for any POST/PUT requests to form-handling endpoints with large payloads, or test by sending a large URL-encoded body to your form endpointsAffected if Form-encoded endpoints are externally accessible and no size-based throttling is enforced at the Undertow or proxy layer
You are affected if Undertow is present with an unpatched version and your application exposes endpoints that handle application/x-www-form-urlencoded data without enforced request body size limits.
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 request body size limits and timeout constraints on the Undertow server configuration to prevent excessive memory allocation from large form submissions. Consider using max-request-size limits and enabling streaming parsers where possible.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2024-3884 — 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-2024-3884 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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- Version or environment caveats, and links to real fixes
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