CVE-2023-1973
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 package. Using the FormAuthenticationMechanism, a malicious user could trigger a Denial of Service by sending crafted requests, leading the server to an OutofMemory error, exhausting the server's memory.
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 vulnerability in Undertow's FormAuthenticationMechanism allows attackers to trigger an OutOfMemory error by sending crafted authentication requests, causing memory exhaustion and denial of service.
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 usage in your environmentSearch for undertow-core jar files in your application deployment, check pom.xml or build.gradle dependencies for undertow dependency, or review WAR/EAR file contentsAffected if Undertow is present as a dependency or deployed component
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Determine the installed Undertow versionCheck the version of undertow-core in your Maven/Gradle dependency tree, or inspect the MANIFEST.MF file inside the undertow-core.jar for the Implementation-Version attributeAffected if The version is older than the patched release for CVE-2023-1973 (compare against Undertow security advisories)
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Verify form-based authentication is enabledCheck your application's web.xml for <form-login> configuration under <login-config>, or search codebase for FormAuthenticationMechanism usage or undertow authentication configurationAffected if Form-based authentication (FORM) is configured as the authentication mechanism
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Inspect memory consumption during authenticationMonitor JVM heap usage and look for abnormal growth in memory when processing repeated form login submissions, particularly with large request bodiesAffected if Heap memory grows abnormally or approaches OutOfMemory conditions during form authentication requests
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Check for rate limiting on authentication endpointsReview any existing request filters, web application firewall rules, or Undertow handler configurations that limit login request frequency or sizeAffected if No rate limiting or size constraints exist on form login endpoints
You are affected if Undertow with form-based authentication is in use and the version has not been patched for CVE-2023-1973, especially without request rate limiting in place.
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 Undertow to a patched version; implement request rate limiting and size constraints on form authentication to mitigate memory exhaustion while patching.
- 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-2023-1973 — 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-2023-1973 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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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