CVE-2018-12541
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 · uneditedIn version from 3.0.0 to 3.5.3 of Eclipse Vert.x, the WebSocket HTTP upgrade implementation buffers the full http request before doing the handshake, holding the entire request body in memory. There should be a reasonnable limit (8192 bytes) above which the WebSocket gets an HTTP response with the 413 status code and the connection gets closed.
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 confidenceThe WebSocket HTTP upgrade implementation in Eclipse Vert.x versions 3.0.0 through 3.5.3 buffers the complete HTTP request in memory before performing the WebSocket handshake without enforcing any size limit. This allows oversized HTTP upgrade requests to consume excessive memory, potentially leading to resource exhaustion. The fix should enforce an 8192-byte limit and return HTTP 413 (Payload Too Large) with connection closure for requests exceeding this threshold.
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>= 3.0.0, < 3.5.4CVSS 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:3.1/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.
-
Identify Eclipse Vert.x installationLocate the Vert.x libraries in your deployment - check Java classpath, dependencies (Maven pom.xml, Gradle build.gradle), or application packaging for vertx-core or vertx-web jarsAffected if Eclipse Vert.x is present in your environment
-
Determine Vert.x versionInspect the vertx-core or vertx-web JAR file manifest, or check your dependency management file (pom.xml, build.gradle) for the exact version numberAffected if Version is 3.0.0 through 3.5.3 inclusive (any version >= 3.0.0 and < 3.5.4)
-
Verify WebSocket upgrade usageSearch your application code for WebSocket handler registration - look for Router.route() with .handler() using io.vertx.ext.web.handler.sockjs.SockJSHandler or direct WebSocket routing, or check HttpServer request handlers for websocket() method callsAffected if Your application accepts WebSocket connections via HTTP upgrade requests
-
Inspect WebSocket upgrade configurationCheck your Vert.x configuration files or code for any existing HTTP upgrade request size limits - the vulnerable versions have no limit enforcement on the Upgrade request bufferAffected if No limit is configured on WebSocket upgrade requests and the version falls within the affected range
You are affected if your environment runs Eclipse Vert.x version 3.0.0 through 3.5.3 and accepts WebSocket connections without any request size limit on the HTTP upgrade handshake.
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 data3.5.4
Upgrade Eclipse Vert.x to version 3.5.4 or later, which implements the 8192-byte limit on WebSocket upgrade requests and returns HTTP 413 with connection closure for oversized requests.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 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 $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-12541 — 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-2018-12541 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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
- No spam, self-promotion, credentials, or personal data