OpenAI Codex Desktop for Windows and macOS automatically inspected Git metadata and working-tree status when a user opened a workspace. If the workspace contains a repository with preserved attacker-controlled .git/config, the attr.tree setting and a configured clean or process filter can cause Git to run an attacker-controlled program. The program runs outside Codex's command sandbox with the signed-in user's privileges, without a workspace-trust prompt, command approval, or interaction with a model. The attacker can read, modify, or delete files and access credentials available to that user. Exploitation requires Git to be available on PATH and the user to open the attacker-prepared repository with its local Git configuration intact. An ordinary Git clone does not copy the source repository's .git/config and is not sufficient by itself.

OpenAI Codex CLI for Windows, macOS, and Linux and Codex Desktop for Windows and macOS automatically collected Git repository metadata without disabling the repository-local core.fsmonitor setting. If a user opens or uses an attacker-prepared repository whose preserved .git/config sets core.fsmonitor to an attacker-controlled filesystem-monitor helper, Git can execute that helper while Codex collects repository metadata. The helper runs outside Codex's command sandbox and without a user-approval prompt, allowing attacker-controlled code to run with the user's privileges. The code can read, change, or delete the user's files and access other resources available to the user's account. An ordinary Git clone does not preserve the source repository's local .git/config; exploitation requires a repository delivered or copied with that configuration intact.

OpenAI Codex Desktop for Windows and macOS could execute attacker-controlled Git hooks because automated Git operations trusted the repository's local core.hooksPath setting. If a user opens an attacker-prepared repository whose preserved .git/config points core.hooksPath to an attacker-controlled directory, Codex can run a malicious hook while processing the repository. The hook executes outside Codex's command sandbox, without user approval, and with the user's privileges, allowing it to read, change, or delete the user's files and access other resources available to the user's account. An ordinary Git clone does not preserve the attacker-controlled repository-local configuration required for exploitation.