DoS via StaticHandler cache in Eclipse Vert.x Web <4.5.23/5.0.6
CVE-2026-1002 Published on January 15, 2026
Eclipse Vert.x Web static handler file access denial
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);
Weakness Type
What is a HTTP Request Smuggling Vulnerability?
When malformed or abnormal HTTP requests are interpreted by one or more entities in the data flow between the user and the web server, such as a proxy or firewall, they can be interpreted inconsistently, allowing the attacker to "smuggle" a request to one device without the other device being aware of it.
CVE-2026-1002 has been classified to as a HTTP Request Smuggling vulnerability or weakness.
Products Associated with CVE-2026-1002
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Affected Versions
Eclipse Vert.x:- Version 4.0.0, <= 4.5.23 is affected.
- Version 5.0.0, <= 5.0.6 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.