UndertowApplication · Redhat
CVE-2020-10705
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 discovered in Undertow in versions before Undertow 2.1.1.Final where certain requests to the "Expect: 100-continue" header may cause an out of memory error. This flaw may potentially lead to a denial of service.
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 versions prior to 2.1.1.Final. The web server's handling of HTTP requests containing the 'Expect: 100-continue' header can be triggered to cause excessive memory allocation, resulting in out-of-memory errors.
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
UndertowApplication
< 2.1.1
Jboss Enterprise Application PlatformApplication
all versions= 7.2
Openshift Application RuntimesApplication
all versionsall versionsCVSS 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 installationSearch for undertow-core*.jar files in the application directory, or check Maven/Gradle dependencies for undertow-core. For JBoss EAP, examine the module path for the undertow-core module.Affected if Undertow is present and the version cannot be determined or is below 2.1.1.Final
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Check Undertow versionFor standalone JAR: run 'java -jar undertow-core*.jar --version' if available, or inspect the JAR manifest file (META-INF/MANIFEST.MF) for the Implementation-Version attribute. For Maven/Gradle: review pom.xml or build.gradle for the undertow-core version declaration.Affected if The installed or declared Undertow version is less than 2.1.1.Final
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Verify HTTP service exposureConfirm the Undertow-based HTTP server is listening on a network port (typically 8080, 8443, or a custom port). Use 'netstat -tlnp' or 'ss -tlnp' to list listening ports.Affected if An HTTP service powered by a vulnerable Undertow version is accessible over the network
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Check product-specific Undertow usageFor Red Hat JBoss EAP 7.2, examine the server startup logs for Undertow subsystem initialization. For NetApp Oncommand Insight, locate the bundled Undertow JAR in the installation directory and verify its version from the filename or manifest.Affected if The product bundles Undertow and the bundled version is below 2.1.1.Final
A user is affected if their environment runs Undertow (directly or embedded in JBoss EAP/Netapp Oncommand Insight) with a version prior to 2.1.1.Final and the HTTP service is network-accessible to receive the 'Expect: 100-continue' header.
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 data2.1.1
Upgrade Undertow to version 2.1.1.Final or later. As a temporary workaround, consider implementing request filtering or rate limiting at a reverse proxy or load balancer to block malformed Expect headers.
Fix this in Undertow
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 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 $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-10705 — 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-2020-10705 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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