Sandbox mode fails in Gemini CLI 0.42.0 with "Unknown argument: c"; works in 0.41.2

[Muhammad-Haziq911]

What happened?

Gemini CLI sandbox mode appears to be broken in version 0.42.0.

When I run Gemini CLI normally without sandboxing, it starts successfully. However, when I enable Docker sandboxing using either -s or GEMINI_SANDBOX=docker, Gemini CLI exits immediately with:

Unknown argument: c

### What did you expect to happen?

The issue only appears after enabling sandboxing. Normal Gemini CLI startup worked before sandboxing was enabled.
The same machine, same Docker installation, same repo, and same user account work correctly after downgrading to 0.41.2, so this looks like a regression in 0.42.0.

### Client information

About Gemini CLI                                                                                                                                      
CLI Version                                         0.41.2                                                                                           
Git Commit                                          b0c7a17                                                                                           
Model                                               Auto (Gemini 3)                                                                                   
Sandbox                                             sandbox-0.41.2-0                                                                                  
OS                                                  linux                                                                                             
Auth Method                                         Signed in with Google                
Tier                                                Gemini Code Assist in Google One AI Pro  

### Login information

Google Account

### Anything else we need to know?

Gemini CLI version with issue: 0.42.0
Gemini CLI version that works: 0.41.2
Installed via: npm
OS: Linux / Ubuntu
Kernel: 6.8.0-52-generic
Node: v24.15.0 via NVM
Shell/terminal: GNOME Terminal / Ubuntu terminal
Sandbox provider: Docker
Auth type: OAuth personal
Docker: working without sudo

[gemini-cli]

Found possible duplicate issues:

• Sandboxing completely broken in v0.42.0: "Unknown argument: c" #26964
• Can't Access Sandbox mode. #27108
• This is a common problem #26981

If you believe this is not a duplicate, please remove the status/possible-duplicate label.