Linux sandboxed exec_command fails in 0.131.0-0.133.0

What version of Codex CLI is running?

0.133.0

What subscription do you have?

Plus

Which model were you using?

_No response_

What platform is your computer?

_No response_

What terminal emulator and version are you using (if applicable)?

_No response_

Codex doctor report

What issue are you seeing?

On Linux, Codex CLI versions 0.131.0 through 0.133.0 fail to run normal sandboxed agent shell commands through exec_command. The failure occurs before the requested command starts.

Rolling back to 0.130.0 fixes the issue.

What steps can reproduce the bug?

Ask Codex to run a trivial shell command such as: pwd.
The same failure occurs if the shell is explicitly set to /bin/sh.

The agent shell command fails before the command runs:

exec_command failed for `/home/USER/.local/bin/zsh -lc pwd`:
CreateProcess { message: "Rejected(\"Failed to create unified exec process: No such file or directory (os error 2)\")" }

Explicit /bin/sh fails the same way:

exec_command failed for `/bin/sh -lc pwd`:
CreateProcess { message: "Rejected(\"Failed to create unified exec process: No such file or directory (os error 2)\")" }

The same setup works after downgrading to Codex CLI 0.130.0.

Environment

• Ubuntu 22.04 (6.8.0-79-generic)
• Affected Codex CLI versions: 0.131.0, 0.132.0, 0.133.0
• Using the vendored bwrap / Linux sandbox components from Codex

Config:

approval_policy = "on-request"
sandbox_mode = "read-only" # also reproduced with "workspace-write"

What is the expected behavior?

Normal sandboxed agent commands such as pwd, ls, sed, and rg should run successfully, subject to the configured sandbox permissions.

Additional information

The standalone sandbox smoke test succeeds:

codex sandbox linux -- pwd

So the Linux sandbox launcher / bwrap path appears functional. The regression seems specific to the normal agent exec_command / unified-exec path.