Dockhand before 1.0.55 Arbitrary File Read via Stack Adoption Compose Path

Dockhand before 1.0.55 contains an arbitrary file read vulnerability that allows authenticated users with stacks:create permission to read sensitive files by supplying an arbitrary composePath during stack adoption. Attackers can adopt a stack pointing to the encryption key, SQLite database, or /proc/self/environ and read it via the compose endpoint to obtain all stored credentials.