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".
The OAuth2 Hawk and JOSE MAC Validation code in Apache CXF prior to 3.0.13 and 3.1.x prior to 3.1.10 is not using a constant time MAC signature comparison algorithm which may be exploited by sophisticated timing attacks.
JAX-RS XML Security streaming clients in Apache CXF before 3.1.11 and 3.0.13 do not validate that the service response was signed or encrypted, which allows remote attackers to spoof servers.
Apache CXF's STSClient before 3.1.11 and 3.0.13 uses a flawed way of caching tokens that are associated with delegation tokens, which means that an attacker could craft a token which would return an identifer corresponding to a cached token for another user.