A vulnerability in GitLab CE/EE versions from 17.6.5 before 19.3.6, 19.4 before 19.4.3, and 19.5 before 19.5.1 allowed an unauthenticated user to retrieve sensitive internal server credentials due to improper filtering of internal response headers. This issue has been fixed in versions 19.3.6, 19.4.3, and 19.5.1.