CVE-2018-8039 is a high-severity (CVSS 8.1) CWE-755 vulnerability in org.apache.cxf:cxf-rt-transports-http. O3 Security confirms whether CVE-2018-8039 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Apache CXF TLS hostname verification does not work correctly with com.sun.net.ssl.*
Real-World Exposure
org.apache.cxf:cxf-rt-transports-http☕org.apache.cxf:cxf-rt-transports-http☕org.apache.cxf:apache-cxf☕org.apache.cxf:apache-cxfReal-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
It is possible to configure Apache CXF to use the com.sun.net.ssl implementation via 'System.setProperty("java.protocol.handler.pkgs", "com.sun.net.ssl.internal.www.protocol");'. When this system property is set, CXF uses some reflection to try to make the HostnameVerifier work with the old com.sun.net.ssl.HostnameVerifier interface. However, the default HostnameVerifier implementation in CXF does not implement the method in this interface, and an exception is thrown. However, in Apache CXF prior to 3.2.5 and 3.1.16 the exception is caught in the reflection code and not properly propagated. What this means is that if you are using the com.sun.net.ssl stack with CXF, an error with TLS hostname verification will not be thrown, leaving a CXF client subject to man-in-the-middle attacks.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.cxf:cxf-rt-transports-http | ≥ 3.2.0&&< 3.2.5 | 3.2.5 |
| ☕Maven | org.apache.cxf:cxf-rt-transports-http | all versions | 3.1.16 |
| ☕Maven | org.apache.cxf:apache-cxf | ≥ 3.2.0&&< 3.2.5 | 3.2.5 |
| ☕Maven | org.apache.cxf:apache-cxf | all versions | 3.1.16 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.cxf:cxf-rt-transports-http. 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 org.apache.cxf:cxf-rt-transports-http to 3.2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-8039 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-2018-8039 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-2018-8039. 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-2018-8039 in your dependencies?
O3 detects CVE-2018-8039 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.