UndertowApplication · Redhat
CVE-2018-1114
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 · uneditedIt was found that URLResource.getLastModified() in Undertow closes the file descriptors only when they are finalized which can cause file descriptors to exhaust. This leads to a file handler leak.
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 confidenceUndertow's URLResource.getLastModified() method fails to properly close file descriptors after reading metadata, causing them to accumulate until file descriptor limits are exhausted, leading to a denial-of-service condition.
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
all versions
VirtualizationApplication
= 4.0= 4.2
Virtualization HostApplication
= 4.0CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:L/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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Confirm Undertow is in useIdentify if the Java application uses Undertow as its embedded web server or servlet container. Check application dependencies (Maven pom.xml, WAR lib folders, or container deployment) for undertow-core or jboss-undertow jars.Affected if Undertow is present in the runtime environment
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Check if static resource serving is enabledDetermine if the application serves static content (files, resources) via HTTP through Undertow. Review web server configuration or application code for resource handlers that serve files using URL-based paths.Affected if Static resources are served through Undertow's URLResource mechanism
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Monitor file descriptor accumulationTrack the process file descriptor count over time while the server handles requests. On Linux, use 'ls -la /proc/<pid>/fd | wc -l' or 'lsof -p <pid>' to observe descriptor growth.Affected if File descriptor count continuously increases without releasing or approaches system limits
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Verify system ulimit for open filesCheck the maximum file descriptor limit with 'ulimit -n' or by viewing /proc/sys/fs/file-max. Compare against current usage to determine available headroom.Affected if The system has low file descriptor limits and Undertow is serving content
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Review access patterns triggering getLastModifiedAnalyze HTTP traffic or application logs for requests that would invoke getLastModified() on URL resources, such as conditional GET (If-Modified-Since) headers or initial static file requests.Affected if HTTP clients request static content that triggers Undertow's getLastModified() method
The environment is affected if Undertow serves static resources via URL and file descriptors accumulate without proper cleanup during normal request handling.
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 a patched version of Undertow that properly closes file descriptors in the URLResource.getLastModified() method, or implement file descriptor monitoring and alerting as a compensating control.
Fix this in Undertow
Scoped from the published advisory
- Consultation1.0 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 $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-1114 — 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-2018-1114 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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