Jboss Enterprise Application PlatformApplication · Redhat
CVE-2016-4993
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 · uneditedCRLF injection vulnerability in the Undertow web server in WildFly 10.0.0, as used in Red Hat JBoss Enterprise Application Platform (EAP) 7.x before 7.0.2, allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via unspecified vectors.
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 confidenceCRLF injection vulnerability in Undertow web server allows attackers to inject carriage return and line feed characters into HTTP headers, enabling injection of arbitrary headers and HTTP response splitting. This can lead to cache poisoning, cross-site scripting (XSS), and other attacks via maliciously crafted requests.
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
Jboss Enterprise Application PlatformApplication
<= 7.0.1
Jboss Wildfly Application ServerApplication
= 10.0.0CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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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Identify the installed JBoss or WildFly versionCheck the version file in the installation directory (e.g., $JBOSS_HOME/version.txt or $WILDFLY_HOME/version.txt), or query the system property via the management CLI: /:read-attribute(name=product-version)Affected if The version is WildFly 10.0.0 exactly, or JBoss EAP version 7.0.1 or earlier
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Verify the Undertow subsystem is in useInspect the standalone.xml configuration file (typically in $JBOSS_HOME/standalone/configuration/ or $WILDFLY_HOME/standalone/configuration/) and look for the <subsystem xmlns="urn:jboss:domain:undertow:...> elementAffected if The Undertow subsystem is configured, which is the default web server for these versions
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Confirm the Undertow version if accessibleCheck the module.xml file for the undertow-core module (typically in $JBOSS_HOME/modules/system/layers/base/io/undertow/main/) or list the Undertow JAR files in the modules directoryAffected if The Undertow version corresponds to the vulnerable releases bundled with WildFly 10.0.0 or JBoss EAP 7.0.1 and earlier
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Check if HTTP responses are being generatedReview deployed applications and configuration to confirm the Undertow HTTP listener is active (look for <http-listener> elements in the undertow subsystem of standalone.xml)Affected if An HTTP listener is configured and serving HTTP requests, which enables the CRLF injection attack vector
You are affected if you are running WildFly 10.0.0 or JBoss EAP 7.0.1 or earlier with the Undertow web server subsystem active and handling HTTP requests.
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 WildFly to version 10.0.0 or later, or update JBoss EAP to version 7.0.2 or later. Apply available security patches from Red Hat.
Fix this in Jboss Enterprise Application Platform
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-4993 — 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-2016-4993 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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