CVE-2026-102479 Eclipse Foundation CVE debrief

Who should care

Defenders and administrators using Eclipse Vert.x versions [5.0.0, 5.0.12], [5.1.0, 5.1.9], and 5.2.0 should assess exposure, prioritize remediation, and verify inventory for affected versions. This includes operators, platform administrators, vulnerability management teams, and security teams responsible for ensuring the security and integrity of applications built with Eclipse Vert.x.

Why it matters

CVE-2026-102479 is a high-severity vulnerability in Eclipse Vert.x that allows request smuggling. Defenders should assess exposure, prioritize remediation, and verify inventory for affected versions.

• Potential request smuggling attacks
• Exposure of sensitive data or systems
• Compromise of application integrity
• Verification of inventory and remediation priority

Technical summary

The Vert.x HTTP/1.x decoder uses canonicalization for well-known HTTP headers, allowing crafted headers to be interpreted as headers like Content-Length. This can be exploited for request smuggling purposes. The impacted component is io.vertx:vertx-core, affecting versions [5.0.0, 5.0.12], [5.1.0, 5.1.9], and 5.2.0. Defenders should assess exposure and prioritize remediation for affected versions of Eclipse Vert.x, verifying inventory for io.vertx:vertx-core versions [5.0.0, 5.0.12], [5.1.0, 5.1.9], and 5.2.0, and monitor for potential request smuggling attacks.

Defensive priority

Remediation is recommended for systems using affected versions of Eclipse Vert.x. Verify inventory for io.vertx:vertx-core versions [5.0.0, 5.0.12], [5.1.0, 5.1.9], and 5.2.0.

Recommended defensive actions

• Assess exposure for systems using io.vertx:vertx-core versions [5.0.0, 5.0.12], [5.1.0, 5.1.9], and 5.2.0
• Prioritize remediation for affected versions
• Verify inventory for Eclipse Vert.x versions
• Monitor for potential request smuggling attacks
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the affected versions and potential exploitation. However, limited information is available on actual attacks or victim organizations. Defenders should verify inventory for io.vertx:vertx-core versions [5.0.0, 5.0.12], [5.1.0, 5.1.9], and 5.2.0, and assess exposure to potential request smuggling attacks.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.