CVE-2026-1002: eclipse vert.x HTTP Request/Response Smuggling

Vulnerability summary

CVE-2026-1002 is a medium (CVSS 6.9) HTTP Request/Response Smuggling vulnerability in eclipse vert.x. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 15-01-2026
   PublishedVulnerability first disclosed.
2. 15-01-2026
   Last modifiedVulnerability information updated.

Description

The Vert.x Web static handler component cache can be manipulated to deny the access to static files served by the handler using specifically crafted request URI. The issue comes from an improper implementation of the C. rule of section 5.2.4 of RFC3986 and is fixed in Vert.x Core component (used by Vert.x Web): https://github.com/eclipse-vertx/vert.x/pull/5895 Steps to reproduce Given a file served by the static handler, craft an URI that introduces a string like bar%2F..%2F after the last / char to deny the access to the URI with an HTTP 404 response. For example https://example.com/foo/index.html can be denied with https://example.com/foo/bar%2F..%2Findex.html Mitgation Disabling Static Handler cache fixes the issue. StaticHandler staticHandler = StaticHandler.create().setCachingEnabled(false);

• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.