Key points
- CVE-2026-102461 is rated CVSS 8.7 High by the National Vulnerability Database.
- The flaw affects Eclipse Vert.x versions 4.0.0 through 5.2.0 in specific ranges.
- The vulnerability allows remote unauthenticated denial of service attacks.
Eclipse Vert.x versions 4.0.0 through 4.5.34, 5.0.0 through 5.0.12, 5.1.0 through 5.1.9, and 5.2.0 are vulnerable to a denial-of-service attack according to the National Vulnerability Database. The issue stems from how the software validates JSON data. A remote attacker who does not need authentication can exploit this weakness. The vulnerability is classified as high severity with a CVSS score of 8.7. Small businesses using these development frameworks need to understand the risk immediately.
In plain English
The problem lies in the `io.vertx:vertx-json-schema` component. When the system checks if items in a JSON array are unique, it compares every item against every other item. This process uses a quadratic algorithm that slows down significantly as the list grows. An attacker can send a moderately sized array that forces the server to consume disproportionate CPU time. This leads to denial of service.
The background
Several other Vert.x modules rely on the vulnerable schema component. The `io.vertx:vertx-web-openapi-router`, `io.vertx:vertx-web-validation`, and `io.vertx:vertx-openapi` modules are also affected because they depend on the flawed library. The Eclipse Foundation lists these versions as impacted. The vulnerability exists because the validation loop lacks a size limit or a shortcut to stop processing early. This allows disproportionate CPU consumption from relatively small inputs.
What changes now
The source material does not state whether a fix exists. Administrators cannot confirm if a patch is available based on the provided records. Teams must monitor official Eclipse channels for updates regarding remediation. In the meantime, the risk remains active for any system running the listed versions. Organizations should prepare to test updates as soon as they become available. Until then, exposure management is the primary defense strategy for affected infrastructure.
Who needs to act first
Teams should prioritize updating systems that face the internet directly. Check whether your web servers accept JSON payloads from unknown users. Isolate vulnerable instances behind strict network controls if possible. Verify that backup procedures are current before making any changes. Test any future updates in a safe environment first. Do not assume internal systems are safe if they share libraries with public-facing apps.
What to do and how to stay safe: Eclipse Vert.x
- Restrict network access to vulnerable servers to only trusted IP addresses where possible.
- Monitor server CPU usage for sudden spikes that indicate a potential attack.
- Review application logs for unusually large JSON requests coming from external sources.
- Once the vendor provides an update, test it thoroughly before deploying to production.
Step-by-step guide: Out-of-Band Patches: Meaning, Risks, and Deployment Reality
General security guidance from the Patch Herald newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
Is there a patch for CVE-2026-102461?
The source material does not mention whether a fix or patch exists for this vulnerability.
Which versions of Eclipse Vert.x are affected?
Versions 4.0.0 through 4.5.34, 5.0.0 through 5.0.12, 5.1.0 through 5.1.9, and 5.2.0 are affected.
What is the severity of this vulnerability?
The National Vulnerability Database rates CVE-2026-102461 as High with a CVSS score of 8.7.
