CVE-2011-4461
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 · uneditedJetty 8.1.0.RC2 and earlier computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.
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 confidenceJetty 8.1.0.RC2 and earlier computes hash values for form parameters using Java's String.hashCode() without restricting predictable hash collisions, allowing remote attackers to send crafted parameter sets that trigger computational O(n²) behavior, causing CPU exhaustion and 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= 6.9.0<= 8.1.0= 1.0= 1.0.1= 1.1= 1.1.1= 1.2.0= 1.3.0= 1.3.1= 1.3.2= 1.3.3= 1.3.4= 1.3.5CVSS 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
- Low
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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 if Jetty is installedLook for Jetty installation directories (jetty-distribution, start.jar) or running Jetty processes. Check common paths: /opt/jetty, /usr/share/jetty, or application-specific bundling.Affected if Jetty server software is present in the environment
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Determine the Jetty versionCheck the Jetty version file (version.txt in the Jetty home directory), or inspect the start.jar manifest, or review startup logs for the Jetty version number.Affected if The installed version matches <= 8.1.0, 8.1.0.RC2, or any of these: 1.0, 1.0.1, 1.1, 1.1.1, 1.2.0, 1.3.0, 1.3.1, 1.3.2, 1.3.3, 1.3.4, 1.3.5
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Verify Oracle Sun Storage Common Array Manager versionIf the product is Oracle Sun Storage Common Array Manager, check its version through the management interface or system information files.Affected if The version is exactly 6.9.0 and it bundles the affected Jetty version
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Confirm form parameter handling is in useReview application configuration (web.xml, context files) to determine if the application accepts form submissions (POST requests with application/x-www-form-urlencoded content-type).Affected if The application processes form parameters via Jetty's request handling, which is enabled by default
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Check if hash randomization is implementedReview the Jetty source code or library files for the presence of hash randomization in the Request parameter handling code. Look for the use of java.util.HashMap with randomized hashing or custom parameter hash implementations.Affected if The installed Jetty lacks hash randomization in its parameter handling, meaning String.hashCode() is used directly without mitigation
You are affected if Jetty version is 8.1.0.RC2 or earlier, or any 1.x version (1.0 through 1.3.5), or Oracle Sun Storage Common Array Manager 6.9.0 is in use, and the server processes form parameters.
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 Jetty 8.1.1 or later which implements hash randomization and/or apply request parameter limits; alternatively, implement a servlet filter to restrict parameter count and reject requests with excessive parameters.
- Consultation3.0 h
- Implementation5.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-4461 — 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-2011-4461 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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