In Eclipse Vert.x versions [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the Vert.x HTTP/1.x decoder uses a canonicalization for well known HTTP headers, the canonicalization process interprets well crafted headers as headers of this l…

In Eclipse Vert.x versions [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the Vert.x HTTP/1.x decoder uses a canonicalization for well known HTTP headers, the canonicalization process interprets well crafted headers as headers of this list, allowing for instance Content-Xength to be interpeted as Content-Length. This can be exploited for request smuggling purpose. The impacted component is io.vertx:vertx-core.

Source published

14 Oct 2026 18:43:54 UTC

Source modified

16 Oct 2026 18:23:47 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 4.0 · 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N