Executive brief
Apache CXF is an open-source web services framework used to build SOAP and REST web services. The OAuth2 security component contains a logic error that inverts an IP address binding check, causing it to reject legitimate requests from the bound IP address while accepting requests from any other IP address. An attacker with a valid OAuth2 token can replay it from any IP address, completely bypassing the sender-constrained token binding security control and gaining unauthorized access to protected resources.
Technical details
The vulnerability is a logic error (CWE-358) in the OAuthRequestFilter component of Apache CXF's cxf-rt-rs-security-oauth2 module. When IP binding validation is enabled as a security feature, the inverted conditional logic rejects legitimate requests originating from the configured bound IP address while blindly allowing requests from any other IP address. The attack requires the attacker to first obtain a valid OAuth2 access token through a separate vector (token leakage, network interception, or log exposure), but no additional authentication or privileges are required for exploitation. An attacker can then replay the stolen token from any IP address, bypassing the intended sender-constrained token binding protection. Affected versions are 4.2.0 through 4.2.1 and all versions prior to 4.1.7. Fixes are available in Apache CXF versions 4.2.2 and 4.1.7.
Affected products
- Apache CXF 4.2.0 to 4.2.1, before 4.1.7
Timeline
- 2026-06-12: disclosed: Vulnerability disclosed publicly
- 2026-06-12: patched: Patches released in versions 4.2.2 and 4.1.7