All vulnerabilities
CVE-2026-107938

Apache CXF: The Netty HTTP client transport does not perform TLS hostname verification.

Apache Software Foundation Apache CXF
CVSS
9.1Critical
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.20%Chance of exploitation activity in the next 30 days, higher than 9% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in4.2.4Also 4.1.9, 3.6.13CVE List
Published9 Oct 2026Updated 15 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 3

  • Apache CXFaffected: 4.2.0 before 4.2.4CVE List
  • Apache CXFaffected: 4.0.0 before 4.1.9CVE List
  • Apache CXFaffected: all versions before 3.6.13CVE List

References 1