The OpenID Connect Core 1.0 specification mandates that the RP MUST validate the chash parameter when operating in the Hybrid Flow. If an Apache CXF RP is integrated with a non-compliant or misconfigured Identity Provider (IdP) that omits the chash, the RP becomes vulnerable to Authorization Code Substitution/Injection attacks. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.
In Apache CXF's DefaultEncryptingOAuthDataProvider, revoked access tokens still decrypt successfully, and TokenIntrospectionService reports active:true. The same applies to refresh tokens. This violates the RFC stipulations that 'The authorization server MUST invalidate the token.' and 'introspection of a revoked token MUST return {"active":false}'. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.
Apache CXF reads a top-level WSDL through its hardened StaxUtils path, which disables XML DTDs and external entities. However, any <wsdl:import> or <xsd:import> referenced from that top-level WSDL is handed off to WSDL4J, which does not disable DOCTYPE declarations or external entities. As a result, the protections applied to the top-level document do not extend to imported documents, leaving imported WSDL/XSD content vulnerable to XML External Entity (XXE) attacks. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.
Apache CXF allows to set a limit on the number of form parameters in a JAX-RS message via the "maxFormParameterCount" configuration option. However, no default limit is set which may lead to denial of service attacks when processing requests with very large numbers of form parameters. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue by using a default limit of 500 parameters.
A race condition in JCacheCodeDataProvider allows an attacker to redeem a single authorization code multiple times via concurrent requests, resulting in the issuance of multiple distinct, valid access tokens. Users are recommended to upgrade to versions 4.2.3, 4.1.8 or 3.6.12, which fix this issue.
Apache CXF allows to control the maximum attachment size via the "attachment-max-size". Prior to Apache CXF 4.2.3 and 4.1.8 and 3.6.12, there was no default placed on this size, meaning that a denial of service attack is possible if the user doesn't explicitly set the limit. Users should update to Apache CXF 4.2.3 or 4.1.8 or 3.6.12 which fixes this problem by imposing a default attachment size limit of 50mb.
An incomplete fix for CVE-2026-50645 means that it is still possible to perform a denial of service attack on Apache CXF by sending a message with many attachment headers. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.
A potential denial of service vulnerability is present in versions of Apache CXF before 3.5.10, 3.6.5 and 4.0.6. In some edge cases, the CachedOutputStream instances may not be closed and, if backed by temporary files, may fill up the file system (it applies to servers and clients).
In versions of Apache CXF before 3.6.4 and 4.0.5 (3.5.x and lower versions are not impacted), a CXF HTTP client conduit may prevent HTTPClient instances from being garbage collected and it is possible that memory consumption will continue to increase, eventually causing the application to run out of memory
An improper input validation of the p2c parameter in the Apache CXF JOSE code before 4.0.5, 3.6.4 and 3.5.9 allows an attacker to perform a denial of service attack by specifying a large value for this parameter in a token.
The fix for CVE-2025-48913: Apache CXF: Untrusted JMS configuration can lead to RCE was not complete, meaning that another path in the code might lead to code execution capabilities, if untrusted users are allowed to configure JMS for Apache CXF. Users are recommended to upgrade to versions 4.2.1, 4.1.6 or 3.6.11, which fix this issue.