CVE-2026-2053 in API Manager
Summary
by MITRE • 06/26/2026
The WSO2 API Manager's message flow component, when processing WS-Addressing headers, does not sufficiently validate or restrict user-controlled input within these headers. This omission allows an attacker to manipulate WS-Addressing headers to specify arbitrary destinations for server-initiated requests.
Successful exploitation allows an unauthenticated attacker to control the destination of server-initiated requests originating from the WSO2 API Manager. This direct control can enable unauthorized access to internal network resources or services that would typically be inaccessible from external networks.
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Analysis
by VulDB Data Team • 06/26/2026
The vulnerability in WSO2 API Manager's message flow component represents a critical security flaw that undermines the integrity of the system's request handling mechanisms. This issue specifically manifests within the WS-Addressing header processing functionality where insufficient input validation creates an attack surface for malicious actors to manipulate server behavior. The WS-Addressing protocol is designed to enable communication between web services by providing addressing information for messages, but when improperly validated, it becomes a vector for unauthorized control over outbound communications from the API Manager.
The technical flaw stems from inadequate sanitization and validation of user-controlled data within WS-Addressing headers during message processing. This vulnerability allows attackers to inject malicious destination URLs or service endpoints that will be used by the API Manager's server-initiated requests. The implementation lacks proper restrictions on input parameters, particularly in the ReplyTo and FaultTo header fields where external parties can specify arbitrary endpoints for response delivery. According to CWE-20, this represents a classic input validation vulnerability where insufficient checks on user-supplied data lead to security consequences.
The operational impact of this vulnerability extends beyond simple information disclosure or unauthorized access. An unauthenticated attacker can leverage this weakness to redirect server-initiated requests to controlled external endpoints, potentially enabling man-in-the-middle attacks or service enumeration. The attack vector allows for internal network reconnaissance by routing requests through the API Manager to internal services that would normally be protected by firewall rules or network segmentation. This capability directly violates the principle of least privilege and can result in unauthorized access to sensitive backend systems.
Security professionals should recognize this vulnerability as a potential entry point for lateral movement within network environments, particularly when WSO2 API Manager is deployed in enterprise networks with complex internal service architectures. The ATT&CK framework's T1071.004 technique of application layer protocol manipulation can be effectively executed through this vulnerability to control outbound communication patterns and potentially establish command and control channels. Organizations should implement immediate mitigations including strict input validation for WS-Addressing headers, network segmentation, and monitoring for unusual outbound request patterns from the API Manager.
The recommended remediation approach involves implementing comprehensive input validation that restricts WS-Addressing header values to predefined trusted domains or IP ranges while maintaining support for legitimate use cases. Network-level controls should be deployed to monitor and restrict outbound connections from the API Manager to prevent unauthorized destinations. Additionally, organizations should consider implementing webhook validation mechanisms and certificate-based authentication for server-initiated requests to ensure that only authorized endpoints can receive responses from the API Manager. Regular security assessments and penetration testing should verify that input validation controls remain effective against evolving attack techniques targeting similar vulnerabilities in web service frameworks.