Applications using the “Sensitive Headers” functionality in Spring Cloud Netflix Zuul 2.2.6.RELEASE and below may be vulnerable to bypassing the “Sensitive Headers” restriction when executing requests with specially constructed URLs. Applications that use Spring Security's StrictHttpFirewall (enabled by default for all URLs) are not affected by the vulnerability, as they reject requests that allow bypassing.

An issue was discovered in Zuul 3.x before 3.1.0. If nodes become offline during the build, the no_log attribute of a task is ignored. If the unreachable error occurred in a task used with a loop variable (e.g., with_items), the contents of the loop items would be printed in the console. This could lead to accidentally leaking credentials or secrets.