HTTP Request Smuggling Affecting io.vertx:vertx-core package, versions [5.0.0,5.1.10)[5.2.0,5.2.1)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-IOVERTX-20948698
- published15 Oct 2026
- disclosed14 Oct 2026
- creditMike Read
Introduced: 14 Oct 2026
NewCVE-2026-102479 (opens in a new tab)How to fix?
Upgrade io.vertx:vertx-core to version 5.1.10, 5.2.1 or higher.
Overview
io.vertx:vertx-core is a tool-kit for building reactive applications on the JVM.
Affected versions of this package are vulnerable to HTTP Request Smuggling due to inconsistent interpretation of headers in the isContentLength and isContentType helpers of the VertxHttpRequestDecoder class, which resolve a header name from its length and a subset of its bytes without checking the character at offset 8. An attacker can smuggle a request past a front-end intermediary by sending a header such as Content-Xength, which the decoder treats as Content-Length while the intermediary sees an unrecognized header and does not use it to frame the message. This requires an HTTP/1.x chain in which a proxy or load balancer sits ahead of the server and resolves header names differently.