CVE-2026-102479: vert.x Request Smuggling — Fix

Description

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.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0034

Probability of exploitation

0.27%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-444 CWE-444

Affected Products

Vendor	Product	Versions
eclipse	vert.x	5.0.0 — 5.1.10
eclipse	vert.x	All

References

Advisories & Patches

https://github.com/eclipse-vertx/vert.x/security/advisories/GHSA-ch7p-g5pm-3gqx

Other References

https://gitlab.eclipse.org/security/cve-assignment/-/work_items/352

Frequently Asked Questions

What is CVE-2026-102479? +

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. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-102479? +

CVE-2026-102479 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0034, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-102479? +

CVE-2026-102479 affects products from eclipse, specifically: vert.x. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-102479? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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