Sandbox fails on overmounts

“Shell tools in codex exec -s read-only and -s workspace-write fail the same way, so only danger-full-access works.”

Is this your bug? What gets counted gets fixed. Pile on.

Paste this into your agent. It files your report, with your error and version.

I hit this bug: rapsheet.dev/sheets/codex/issues/15226/file
Follow it to file my report. Show me the text before you send.

No install. No account. Public and anonymous. The link asks your agent for one report, nothing else. What it sends

Fading. No reports and thumbs-up in the last 7 days and 1 the week before, down from 2 a week at the late-September peak. A workaround is known.

Linux sandbox fails on overmounted paths before commands run. Bubblewrap setup rejects or fails on a daemon socket alias under a mount hidden by a later overmount, such as /nix or /tmp.

Is this your bug?

File my report

Where: Linux sandbox
Error text: error building bubblewrap command: app-server socket directory has an unsupported host mount at /nix; remove the bind-mount alias or nested mount before starting the sandbox
Versions: 0.156.0
Platforms: Linux
How bad: Breaks a normal workflow. Some reports say it used to work. Some reports say it blocks them completely.

Part of: Linux sandbox rejects host mounts4 bugs

Sandbox mountinfo path error81 people
WSL2 sandbox fails to start36 people
Sandbox socket mount isolation fails10 people

Original reports3, newest first

Oct 27, 2026Linux sandbox: covered mount aliases still passed to Bubblewrap in 0.164.0 and current main (#47455 regression)On GitHub#57520
Sep 27, 2026Bug: Bubblewrap sandbox fails on HPC with overmounted /tmpOn GitHub#48758
Sep 23, 2026Linux sandbox treats a fully overmounted mount as an app-server socket alias (breaks nix-user-chroot 2.x)On GitHub#47455