ChatGPT VS Code extension 26.707.41301

What version of the IDE extension are you using?

ChatGPT VS Code extension 26.707.41301

What subscription do you have?

team

Which IDE are you using?

VS Code

What platform is your computer?

Host: Ubuntu 24.04 LTS Kernel 6.17 Remote: VS Code Dev Container Ubuntu 22.04

What issue are you seeing?

When using the ChatGPT VS Code extension (openai.chatgpt 26.707.41301) inside a VS Code Dev Container, Codex Agent fails to initialize its filesystem sandbox.

The Output log shows:

codex_core::tools::router: error=apply_patch verification failed:
fs sandbox helper failed with status exit status: 1:
bwrap: loopback: Failed RTM_NEWADDR: Operation not permitted

As a result, operations that rely on the filesystem sandbox fail, including apply_patch verification. Earlier in the chat, the agent also reported that sandbox initialization failed due to the network namespace.

The issue occurs even though the container itself supports network namespaces when running as root.

What steps can reproduce the bug?

1. Host OS: Ubuntu 24.04 LTS.
2. Open a Ubuntu 22.04 Dev Container in VS Code.
3. Install the ChatGPT extension (openai.chatgpt 26.707.41301).
4. Open a Git repository inside the container.
5. Ask Codex Agent to modify a file using apply_patch (or perform another filesystem operation that uses the sandbox).
6. The filesystem sandbox initialization fails with:

bwrap: loopback: Failed RTM_NEWADDR: Operation not permitted

1. apply_patch verification fails because the sandbox helper cannot start.

What is the expected behavior?

If the sandbox cannot be initialized because the current environment does not permit configuring a network namespace or loopback interface, Codex should gracefully fall back instead of failing filesystem operations.

At minimum, when "Allow Unsandboxed Commands" is enabled, safe operations such as apply_patch verification and other read/write operations should either:

• run outside the sandbox after confirmation, or
• provide a clear fallback path.

The extension should not make normal editing workflows unusable because sandbox initialization failed.

Additional information

Environment

Host:

• Ubuntu 24.04
• Linux 6.17.0

Container:

• Ubuntu 22.04
• VS Code Dev Container

Extension:

• openai.chatgpt 26.707.41301

Investigation

As the normal container user:

$ unshare -n true
Operation not permitted

$ grep Cap /proc/self/status
CapEff: 0000000000000000

As root inside the same container:

unshare -n true

(succeeds)

This indicates that:

• The kernel supports network namespaces.
• The failure only occurs for the unprivileged user used by the extension.
• The sandbox helper (bubblewrap) fails while configuring the loopback interface.

Relevant log:

codex_core::tools::router:
error=apply_patch verification failed:
fs sandbox helper failed with status exit status: 1:
bwrap: loopback: Failed RTM_NEWADDR: Operation not permitted

This appears to be a sandbox compatibility issue in Dev Containers. It would be helpful if Codex could detect this environment and automatically fall back instead of failing filesystem operations.