CVE-2026-19591 Security feature bypass in Codex CLI
Attackers can bypass approval prompts to modify configuration and execute code via malicious repositories in OpenAI Codex CLI and Desktop.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-19591?
CVE-2026-19591 is a high-severity vulnerability in OpenAI Codex CLI, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
OpenAI Codex CLI for Windows, macOS, and Linux and Codex Desktop for Windows and macOS misclassified certain PowerShell commands as safe because their command-safety parser interpreted PowerShell's stop-parsing token (--%) differently than PowerShell itself. If a user opens an attacker-prepared repository and Codex follows its instructions, Codex can run a file-writing Git command without requesting user approval. On macOS and Linux, exploitation additionally requires separately installed PowerShell Core (pwsh) to be invoked. If filesystem protections permit the write, the command can modify Codex's configuration. If Codex later loads the modified configuration, it can launch an attacker-controlled MCP server and execute code with the user's privileges, allowing it to read, change, or delete files accessible to that account. The approval bypass does not disable filesystem sandboxing; the default filesystem sandbox on macOS and Linux can prevent writes outside permitted locations.
Weakness: CWE-150
Which versions are affected by CVE-2026-19591?
How do I fix CVE-2026-19591?
No fix has been published for CVE-2026-19591 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-19591 being exploited?
There is no known exploitation of CVE-2026-19591 in the wild and no public exploit code.
Sources
Also known as GHSA-2frj-4qr5-m2rf.