Vite is a frontend tooling framework for javascript. Prior to versions 6.3.4, 6.2.7, 6.1.6, 5.4.19, and 4.5.14, the contents of files in the project root that are denied by a file matching pattern can be returned to the browser. Only apps explicitly exposing the Vite dev server to the network (using --host or server.host config option) are affected. Only files that are under project root and are denied by a file matching pattern can be bypassed. `server.fs.deny` can contain patterns matching against files (by default it includes .env, .env.*, *.{crt,pem} as such patterns). These patterns were able to bypass for files under `root` by using a combination of slash and dot (/.). This issue has been patched in versions 6.3.4, 6.2.7, 6.1.6, 5.4.19, and 4.5.14.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.