The gh cli is GitHub’s official command line tool. A security vulnerability has been identified in the GitHub CLI that could leak authentication tokens when cloning repositories containing `git` submodules hosted outside of GitHub.com and ghe.com. This vulnerability stems from several `gh` commands used to clone a repository with submodules from a non-GitHub host including `gh repo clone`, `gh repo fork`, and `gh pr checkout`. These GitHub CLI commands invoke git with instructions to retrieve authentication tokens using the `credential.helper` configuration variable for any host encountered. Prior to version `2.63.0`, hosts other than GitHub.com and ghe.com are treated as GitHub Enterprise Server hosts and have tokens sourced from the following environment variables before falling back to host-specific tokens stored within system-specific secured storage: 1. `GITHUB_ENTERPRISE_TOKEN`, 2. `GH_ENTERPRISE_TOKEN` and 3. `GITHUB_TOKEN` when the `CODESPACES` environment variable is set. The…