CVE-2023-24815: Disclosure of classpath resources on Windows when mounted on a wildcard route in vertx-web

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-02-09 · updated 2026-06-17
Weakness: CWE-22

Description

Vert.x-Web is a set of building blocks for building web applications in the java programming language. When running vertx web applications that serve files using `StaticHandler` on Windows Operating Systems and Windows File Systems, if the mount point is a wildcard (`*`) then an attacker can exfiltrate any class path resource. When computing the relative path to locate the resource, in case of wildcards, the code: `return "/" + rest;` from `Utils.java` returns the user input (without validation) as the segment to lookup. Even though checks are performed to avoid escaping the sandbox, given that the input was not sanitized `\` are not properly handled and an attacker can build a path that is valid within the classpath. This issue only affects users deploying in windows environments and upgrading is the advised remediation path. There are no known workarounds for this vulnerability.

Affected products

Eclipse Vert.x: from 4.0.0 before 4.3.8 — fixed in 4.3.8

How to fix

Upgrade to a fixed version: Eclipse Vert.x 4.3.8. Check the vendor advisory for mitigations.

References

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