Summary
High severity vulnerability that affects io.vertx:vertx-web
In version from 3.0.0 to 3.5.2 of Eclipse Vert.x, the CSRFHandler do not assert that the XSRF Cookie matches the returned XSRF header/form parameter. This allows replay attacks with previously issued tokens which are not expired yet.
Impact
A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones. Typical impact: state-changing actions performed as the victim without their consent.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2018-12540? CVE-2018-12540 is a high-severity cross-site request forgery (CSRF) vulnerability in io.vertx:vertx-web (maven), affecting versions >= 3.0.0, < 3.5.3. It is fixed in 3.5.3. A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones.
- Which versions of io.vertx:vertx-web are affected by CVE-2018-12540? io.vertx:vertx-web (maven) versions >= 3.0.0, < 3.5.3 is affected.
- Is there a fix for CVE-2018-12540? Yes. CVE-2018-12540 is fixed in 3.5.3. Upgrade to this version or later.
- Is CVE-2018-12540 exploitable, and should I be worried? Whether CVE-2018-12540 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2018-12540 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2018-12540? Upgrade
io.vertx:vertx-webto 3.5.3 or later.