Recursive remote cleanup can escape the intended directory through nested PowerShell/cmd quoting without a root-path safety stop

Summary

Codex intended to remove one temporary smoke-test directory in my own Parallels Windows 11 build VM. After PowerShell Remove-Item failed because a DLL was still locked, Codex automatically escalated to a stronger recursive deletion through a nested macOS shell → SSH → PowerShell -EncodedCommand → cmd.exe chain.

An incorrect PowerShell/cmd quoting pattern caused the operation to traverse the current Windows drive root instead of the intended temporary directory. The operation ran for approximately 59 seconds before a later tool input sent Ctrl-C.

This issue intentionally omits the complete executable deletion command. The original session is available privately through Codex feedback: 019f82c8-4c41-7f91-ab74-30b3d34c98dc.

OpenAI Support confirmed on 2026-07-21 that the conversation was escalated to a support specialist. Support case 11849398 has been issued.

Environment

• Codex task ID: 019f82c8-4c41-7f91-ab74-30b3d34c98dc
• Codex Desktop / recorded version: 0.145.0-alpha.18
• Recorded model setting: gpt-5.6-sol, effort max
• Host: macOS 27.0 (26A5378n)
• Guest: Windows 11 under Parallels Desktop 26.3.3
• Remote execution: SSH → PowerShell -EncodedCommand → cmd.exe
• sandbox_policy.type: danger-full-access
• approval_policy: never
• permission_profile: disabled
• Support case: 11849398

Expected behavior

• A locked temporary directory should be left in place and reported as a non-blocking cleanup failure.
• A recursive delete must remain inside the unique approved run directory.
• The target OS should normalize and attest the final absolute path before deletion.
• Drive roots, user profiles, Desktop, empty paths, unresolved variables, and run roots should be unconditionally rejected.
• A stronger delete method should not be selected automatically after a safer cleanup method fails.

Actual behavior

1. The final package self-check succeeded.
2. PowerShell cleanup failed on a locked Pillow _imaging DLL.
3. Codex described the lock as temporary and retried with a stronger recursive cmd.exe deletion.
4. A backslash-based quote escape was used even though PowerShell does not use backslash to escape double quotes.
5. No final normalized path, final argv, file count, size estimate, allow-root assertion, or root-deny check was shown before execution.
6. Preserved output contained root-level paths including \pagefile.sys, \PROGRA~1\..., and \Users\....
7. The output was recorded as 1,341 lines but truncated.
8. There was no visible automatic output-anomaly stop. Ctrl-C was sent manually about 59.383 seconds after launch.

Context compaction facts

The rollout contains three compaction events in total:

• 12:45:42.425 UTC+8
• 14:11:50.009 UTC+8
• 15:11:12.425 UTC+8, after the incident

Two compactions therefore occurred before the dangerous command. The latest was 42 minutes 08.604 seconds earlier.

I am not claiming compaction directly caused the incident. The exact smoke-test path was created after the second compaction, and the visible replacement history still contains a higher-level “do not clean or roll back user files” constraint. The compaction-summary bodies are encrypted in the local rollout, so only OpenAI can inspect the complete model-visible pre/post-compaction history.

Approval and remote-boundary concern

The user approved the RC6 build generally. There was no separate confirmation for this recursive deletion command. With approval_policy=never, the SSH tool call executed without an approval prompt.

The local sandbox did not directly delete the guest filesystem; the effect occurred through configured SSH credentials. This means local command safety needs to understand destructive payloads nested inside remote and encoded commands, or the remote worker must enforce its own immutable deletion boundary.

Impact and evidence

• Visible Windows desktop state changed substantially.
• Many system files returned access-denied/in-use errors.
• Exact successful deletion list and recovery rate remain unknown.
• I am not claiming that the entire VM was deleted.
• The original rollout, Parallels logs, screenshots, and metadata were preserved.
• After shutdown, a PVM file-level evidence copy was created and all 20 source-manifest files verified by SHA-256.
• The VM had already restarted once before preservation, which is an explicit limitation.

Requested engineering changes

1. Decode and inspect destructive payloads nested in SSH, PowerShell EncodedCommand, and cmd.exe before execution.
2. Canonicalize the target path on the target OS and bind deletion to an approved directory handle or unique run identity.
3. Hard-block drive roots, UNC roots, user-profile roots, Desktop, workspace roots, run roots, empty strings, and unresolved variables.
4. Do not automatically escalate cleanup methods after a lock or access failure.
5. Require a two-phase dry-run summary with normalized path, count, size, and boundary assertions.
6. Require a fresh, non-bypassable confirmation for large recursive deletion even in full-access/no-approval modes.
7. Add an execution-supervisor kill switch when streamed output suddenly shows system-root or out-of-scope paths.
8. Add negative tests for Bash → SSH → PowerShell → cmd quoting, spaces, trailing slashes, empty variables, current-drive roots, UNC paths, and encoded commands.
9. Preserve final argv, normalized target, approval decision, and timestamped output for incident review.
10. After repeated compaction, rehydrate and display the original destructive-operation boundaries before proceeding.

Private evidence references

• Codex feedback session: 019f82c8-4c41-7f91-ab74-30b3d34c98dc
• OpenAI Support case: 11849398
• Security report, if applicable: N/A — no separate security report filed at time of issue creation

Please let me know the safest private channel for the raw JSONL and logs. They contain local paths and will not be attached publicly without further redaction.