CVE-2026-18505 in Financial Transaction Manager
Summary
by MITRE • 09/23/2026
IBM Financial Transaction Manager (FTM) for RedHat OpenShift is vulnerable to open redirect in the PMP `HostHeaderFilter` (`HostHeaderFilter.java:151`). An unauthenticated attacker can craft a request with a manipulated `Host` header to redirect authenticated operators to attacker-controlled sites, enabling credential phishing.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 09/23/2026
The vulnerability identified within IBM Financial Transaction Manager for RedHat OpenShift represents a significant security flaw located in the PMP HostHeaderFilter component, specifically at line 151 of the HostHeaderFilter.java source file. This issue is classified as an open redirect vulnerability, which occurs when an application accepts user-supplied input and uses it to construct a URL or header value without sufficient validation against a whitelist of trusted domains. In this specific context, the filter fails to properly validate the Host HTTP request header before processing subsequent logic within the financial transaction management platform. The presence of this flaw allows for manipulation of the server's perceived identity during request handling, creating an avenue for attackers to exploit trust relationships between users and the application infrastructure.
From a technical perspective, the exploitation mechanism relies on crafting malicious HTTP requests that include a manipulated Host header value pointing to a domain controlled by the attacker. When authenticated operators or administrators interact with the system, particularly in workflows where redirects are triggered based on host information or session validation states, the vulnerable filter processes this untrusted input directly. Consequently, instead of directing traffic to legitimate internal endpoints within the IBM Financial Transaction Manager environment, the application issues an HTTP redirect response that sends the user's browser to the attacker-specified external site. This behavior bypasses standard security controls because the redirection is initiated by a trusted server component, making it appear as though the official platform is endorsing or facilitating access to the malicious destination.
The operational impact of this vulnerability centers on credential phishing and potential session hijacking scenarios. Since the attack targets authenticated operators, the social engineering aspect is heightened due to the perceived legitimacy of the redirect source. An unauthenticated attacker can lure a victim into clicking a link that appears to originate from or be associated with IBM Financial Transaction Manager for RedHat OpenShift. Once redirected, the operator may encounter a spoofed login page hosted on the attacker's infrastructure designed to mimic the authentic interface. If credentials are entered, they are captured by the adversary, leading to unauthorized access to sensitive financial transaction data and administrative controls within the open shift environment. This compromises the confidentiality and integrity of critical banking or payment processing operations managed by the platform.
This vulnerability aligns with CWE-601, which defines URL Redirection to Untrusted Site (Open Redirect), a common weakness in web applications where insufficient validation allows redirection to arbitrary destinations. Furthermore, from an offensive security framework perspective, this technique corresponds to ATT&CK Tactic TA0001 Initial Access and specifically the MITM Phishing sub-technique or Credential Harvesting via phishing sites enabled by open redirects. The ability to redirect authenticated users is particularly dangerous as it leverages existing trust tokens and session cookies, potentially allowing attackers to bypass multi-factor authentication if the secondary factor relies on domain verification that can be spoofed through this vector.
Mitigation strategies must focus on strict input validation and secure configuration of the HostHeaderFilter component. Developers should implement a whitelist approach for allowed host values rather than attempting to blacklist malicious patterns, which is prone to evasion techniques such as case variations or encoding tricks. Additionally, enabling security headers like Strict-Transport-Security can help enforce HTTPS connections and reduce the risk of man-in-the-middle attacks that might complement this redirect flaw. For immediate remediation, IBM should release a patch that corrects the logic in HostHeaderFilter.java at line 151 to ensure all host values are validated against an explicit list of trusted domains before any redirection or processing occurs. Organizations currently running vulnerable versions must apply these updates promptly and monitor access logs for unusual redirect patterns originating from this specific filter endpoint to detect potential exploitation attempts.