Apache CXF has the ability to integrate with JMX by registering an InstrumentationManager extension with the CXF bus. If the ‘createMBServerConnectorFactory‘ property of the default InstrumentationManagerImpl is not disabled, then it is vulnerable to a man-in-the-middle (MITM) style attack. An attacker on the same host can connect to the registry and rebind the entry to another server, thus acting as a proxy to the original. They are then able to gain access to all of the information that is sent and received over JMX.
Apache CXF ships with a OpenId Connect JWK Keys service, which allows a client to obtain the public keys in JWK format, which can then be used to verify the signature of tokens issued by the service. Typically, the service obtains the public key from a local keystore (JKS/PKCS12) by specifing the path of the keystore and the alias of the keystore entry. This case is not vulnerable. However it is also possible to obtain the keys from a JWK keystore file, by setting the configuration parameter "rs.security.keystore.type" to "jwk". For this case all keys are returned in this file "as is", including all private key and secret key credentials. This is an obvious security risk if the user has configured the signature keystore file with private or secret key credentials. From CXF 3.3.5 and 3.2.12, it is mandatory to specify an alias corresponding to the id of the key in the JWK file, and only this key is returned. In addition, any private key information is omitted by default. "oct" keys, which contain secret keys, are not returned at all.
Apache CXF before 3.3.4 and 3.2.11 does not restrict the number of message attachments present in a given message. This leaves open the possibility of a denial of service type attack, where a malicious user crafts a message containing a very large number of message attachments. From the 3.3.4 and 3.2.11 releases, a default limit of 50 message attachments is enforced. This is configurable via the message property "attachment-max-count".
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.
Apache CXF supports sending and receiving attachments via either the JAX-WS or JAX-RS specifications. It is possible to craft a message attachment header that could lead to a Denial of Service (DoS) attack on a CXF web service provider. Both JAX-WS and JAX-RS services are vulnerable to this attack. From Apache CXF 3.2.1 and 3.1.14, message attachment headers that are greater than 300 characters will be rejected by default. This value is configurable via the property "attachment-max-header-size".