Malicious .git Configs Can Make Claude, Codex, Cursor, and Other AI Agents Run Attacker Code

Visual Studio Code Remote Code Execution Vulnerability

In JetBrains IntelliJ IDEA before 2021.3.1, local code execution via RLO (Right-to-Left Override) characters was possible.

OpenAI Codex CLI and Codex Desktop automatically collect Git repository metadata without disabling the repository-local core.fsmonitor setting, so Git can execute the filesystem-monitor helper named in a repository's .git/config while Codex gathers that metadata. The flaw is triggered when a user opens or works in a repository prepared by an attacker and delivered with its .git/config intact, such as a copied folder or archive, because an ordinary Git clone does not preserve the source repository's local config. The attacker-supplied helper runs outside Codex's command sandbox and without any user-approval prompt, giving the attacker code execution with the user's privileges, including the ability to read, modify, or delete the user's files and access other resources available to that account. Anyone running Codex CLI on Windows, macOS, or Linux or Codex Desktop on Windows or macOS who opens untrusted repositories is exposed, and related reporting indicates the same malicious .git/config pattern also affects other AI coding agents such as Claude and Cursor, although this CVE is scoped to Codex. No exploitation is currently known: there is no public proof-of-concept, EPSS is a low 0.1%, the issue is not in CISA KEV, and it was disclosed through Pwn2Own as ZDI-26-650.

Do: Update Codex CLI and Codex Desktop to the latest available release containing the fix as soon as it is published (no specific fixed version number is provided in the available data). Until updating, avoid opening untrusted repositories delivered with their .git/config intact, and inspect .git/config for a core.fsmonitor entry pointing at an unknown or attacker-supplied helper before working in such a repository with Codex. Note that a plain git clone from a remote does not preserve the malicious local config, so archives, copied directories, and dotfile restoration are the delivery paths to watch.

Claude Code is an agentic coding tool. From 2.1.38 until 2.1.163, Claude Code's worktree handling allowed creation of worktrees named ".git" and navigation to worktrees outside the sandbox context, enabling git directory confusion attacks. By exploiting symlink manipulation and git fsmonitor execution during worktree operations, an attacker could overwrite files in the user's home directory (such as .zshenv), leading to code execution outside of seatbelt sandbox restrictions. Reliably exploiting this required the user to clone a malicious repository containing prompt injection content and run Claude Code against it. This vulnerability is fixed in 2.1.163.

Hermes Agent versions 0.18.2 through 0.21.0 contain an OS command injection flaw (CWE-78) in which the agent's git operations honor the core.fsmonitor setting in a repository's .git/config, letting that setting specify an attacker-controlled command. The attack is triggered when a user opens a crafted repository and sends any message, at which point the agent runs a git status index refresh that executes the injected command in the user's process context. A successful attacker gains arbitrary OS command execution with access to the user's full environment, including configured AI provider API keys, which can be exfiltrated. Anyone running an affected Hermes Agent version who opens untrusted or attacker-supplied repositories is exposed; the attack requires user interaction but no privileges or authentication on the target. No public proof-of-concept, KEV listing, or confirmed in-the-wild exploitation is currently known, and EPSS estimates roughly a 0.9% probability of exploitation within 30 days.

Do: Upgrade Hermes Agent to a release that includes fix commit f6234d0 (i.e., any version newer than 0.21.0) and until then avoid opening untrusted repositories with the agent, or inspect their .git/config for a core.fsmonitor entry before use. Users who opened untrusted repositories while running a vulnerable version should rotate the AI provider API keys present in their environment.

goose is general-purpose AI agent that runs on your machine. Prior to 1.44.0, the `goose review` command runs the system `git` executable to gather the diff for review without stripping attacker-controlled Git configuration. A malicious repository whose `.git/config` sets [`core] fsmonitor = ` causes Git to execute that command on the host during the index refresh performed by `git diff HEAD`. The command runs before goose contacts a model and without a submitted prompt, model call, tool approval, or trust prompt. The context-gathering Git process is not sandboxed and is outside goose's tool-permission model. Arbitrary commands run with the privileges and environment of the user running goose, allowing file access or modification and exfiltration of environment secrets and provider API keys. The vulnerable Git invocations are built by git_command() in crates/goose-cli/src/commands/review/handler.rs and are used by touched_files() and collect_diff() for `git diff --name-only HEAD` and `git diff HEAD`. This issue is fixed in version 1.44.0.