CVE-2024-53858

What it actually does

The gh CLI passes GitHub authentication tokens sourced from GITHUB_ENTERPRISE_TOKEN, GH_ENTERPRISE_TOKEN, or GITHUB_TOKEN (when CODESPACES is set) to git credential.helper for any host encountered during submodule operations in gh repo clone, gh repo fork, and gh pr checkout, causing tokens intended for GitHub to be sent to non-GitHub hosts.

Why it matters to the business

Exposure of authentication tokens can allow unauthorized repository access, data exfiltration, or code changes; the issue affects organizations relying on the gh CLI for repository operations involving external submodules, increasing risk of credential compromise across developer workflows.

How an attack unfolds

An attacker hosts a malicious submodule on an external server and embeds a reference in a repository; when a victim uses affected gh commands to clone, fork, or checkout a pull request, gh configures git to retrieve tokens via credential.helper and forwards valid tokens to the attacker's host.

How to fix it

Upgrade the GitHub CLI to version 2.63.0 or later (commit 1fe14c956d057e6abda50a76d8820a6e668ba70a). After upgrading, revoke any tokens that may have been exposed, review personal security logs and relevant audit logs, and avoid using the listed commands with external submodules until patched.

How to confirm the fix worked

Verify gh version is 2.63.0 or newer; test cloning a repository with an external submodule and confirm no tokens are sent to non-GitHub hosts via credential.helper; inspect environment variables and audit logs for prior usage of GITHUB_ENTERPRISE_TOKEN or GITHUB_TOKEN with external hosts.

Typical attack path

1. Create or compromise a repository containing a git submodule hosted on an attacker-controlled non-GitHub server
2. Publish or share the repository to induce cloning via gh repo clone, gh repo fork, or gh pr checkout
3. Trigger the vulnerable gh command on a system with valid GitHub tokens in environment variables or secure storage
4. Intercept the authentication token forwarded by git to the external host

How to detect it

Examine personal security logs and enterprise audit logs for actions associated with repository cloning, forking, or checkout involving external hosts; search for environment variable usage of GITHUB_ENTERPRISE_TOKEN, GH_ENTERPRISE_TOKEN, or GITHUB_TOKEN during git operations with non-GitHub hosts.

• GITHUB_ENTERPRISE_TOKEN used with external git host
• GH_ENTERPRISE_TOKEN sent via credential.helper
• GITHUB_TOKEN forwarded during submodule clone from non-github.com host

What your security team should do

• Upgrade all instances of the GitHub CLI to 2.63.0 or later immediately
• Revoke and rotate any tokens used with the gh CLI
• Review personal security logs and enterprise audit logs for suspicious clone or authentication events
• Restrict use of gh commands with repositories containing external submodules until validation is complete