CVE-2026-107938
Received Received - Intake

Apache CXF Netty HTTP Client Hostname Verification Bypass

Publication date: 2026-10-09

Last updated on: 2026-10-09

Assigner: Apache Software Foundation

Description
In Apache CXF, the Netty-based HTTP client transport (cxf-rt-transports-http-netty-client) did not verify that the hostname in the server’s TLS certificate matched the host being called. This applied over both HTTP/1.1 and HTTP/2, even when disableCNCheck was left at its default value of false. The certificate chain was validated against the configured trust store, but the endpoint’s identity was not. A network attacker able to intercept traffic could present any certificate trusted by the client, such as a publicly issued certificate for a domain they control, and impersonate the target service. They could then read or modify the exchanged messages, including credentials.  Users are recommended to upgrade to versions 4.2.4 or 4.1.9 or 3.6.13, which fix this issue.

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Meta Information

Published
2026-10-09
Last Modified
2026-10-09
Generated
2026-10-09
AI Q&A
2026-10-09
EPSS Evaluated
N/A
NVD
CVE-2026-107938
EUVD
EUVD-2026-95703

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
Apache Software Foundation Apache CXF 4.2.0
Apache Software Foundation Apache CXF 4.0.0
Apache Software Foundation Apache CXF 0

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Exploitability

CWE
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in Apache CXF's Netty-based HTTP client transport allows an attacker to impersonate a target service by presenting a trusted TLS certificate for a domain they control. The client did not verify if the certificate's hostname matched the actual host being called, enabling interception and modification of exchanged messages, including credentials.

Detection Guidance

This vulnerability can be detected by checking the Apache CXF version in use. Run commands like 'mvn dependency:tree' or 'gradle dependencies' to inspect the Netty-based HTTP client transport (cxf-rt-transports-http-netty-client) version. If the version is below 4.2.4, 4.1.9, or 3.6.13, the system is vulnerable.

Impact Analysis

An attacker could read or alter sensitive data like credentials during transmission. This could lead to unauthorized access to systems, data breaches, or further attacks on connected services. Users relying on Apache CXF for secure communications are at risk if not patched.

Compliance Impact

This vulnerability could violate compliance requirements for data protection and secure transmission, such as GDPR's encryption mandates or HIPAA's safeguards for protected health information. Failure to patch may result in non-compliance penalties and increased exposure to data breaches.

Mitigation Strategies

Upgrade Apache CXF to version 4.2.4 or later, 4.1.9 or later, or 3.6.13 or later. Replace the vulnerable Netty-based HTTP client transport (cxf-rt-transports-http-netty-client) with a patched version to ensure hostname verification is enforced.

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