CVE-2023-24815
MEDIUMDisclosure of classpath resources on Windows when mounted on a wildcard route in vertx-web
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
io.vertx:vertx-webReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.vertx:vertx-web | ≥ 4.0.0&&< 4.3.8 | 4.3.8 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.vertx:vertx-web. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update io.vertx:vertx-web to 4.3.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-24815 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2023-24815 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2023-24815. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-24815 in your dependencies?
O3 detects CVE-2023-24815 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.