CVE-2026-18505 is an open redirect vulnerability (CWE-601) in IBM Financial Transaction Manager (FTM) for RedHat OpenShift, specifically in the PMP HostHeaderFilter (HostHeaderFilter.java:151). An unauthenticated attacker can manipulate the Host header in HTTP requests to redirect authenticated users to attacker-controlled websites. This redirection can be used to conduct credential phishing attacks by misleading operators into providing sensitive information on malicious sites. The vulnerability affects versions >=4.0.6.0 and <=4.0.10.0. There is no indication of known exploits in the wild or available patches at this time.

The vulnerability allows attackers to redirect authenticated users to malicious sites, potentially enabling credential phishing attacks. The confidentiality and integrity of user credentials may be compromised if users are tricked into submitting them to attacker-controlled domains. There is no direct impact on availability. The attack requires user interaction (clicking a manipulated link) and does not require privileges or prior authentication.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should be cautious of unexpected redirects and verify URLs before entering credentials. Organizations should monitor IBM advisories for updates and apply patches promptly once released.