[BUG] Bun segfault/SIGABRT on startup — Ubuntu 26.04.1 LTS (glibc 2.43)

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

Claude Code crashes on every startup attempt (both VSCode extension and
CLI installed via npm) with SIGSEGV or SIGABRT from Bun, before doing
anything. Crash is intermittent in exact signal/address but happens
almost every time.

### What Should Happen?

Claude Code should start normally without crashing.

### Error Messages/Logs

```shell
panic(main thread): Segmentation fault at address 0x5
oh no: Bun has crashed.
https://bun.report/1.4.3/l_1047f2e8mggggQugogC2qqm5Dms3k5Ds8rmsE6jn7tC45x5tC_4y4s5Di92s5Dms3k5Dw9q12Ei/j02E6+jl8Em717+E4hxumC_mz/s5Dms3k5Ds8rmsEkni7yE+9n6kCA2AK

---

panic(main thread): abort() called
oh no: Bun has crashed.
https://bun.report/1.4.3/l_1047f2e8kggggQugggC26wpB63tR2ukKwm+ijCwl+ijCmomyzEimyhyEuwvyzE6pohyE46o02Eq8u52Emkw52Euw4nlC_i92s5Di92s5D_i92s5Dms3k5D0k7msEAa

---

panic(main thread): abort() called
oh no: Bun has crashed.
https://bun.report/1.4.3/l_1047f2e8kggggQkgggC26wpB63tR2ukKwm+ijCwl+ijCmomyzEimyhyEi8xhyEuwvyzE6pohyEg2v12Eun8z2E6+jl8Em717+Eiwn6kC2kkl8Em717+Eq1wtlCm+ly/C4i9x/CAa
```

### Steps to Reproduce

1. Fresh install of Ubuntu 26.04.1 LTS (kernel 7.0.0-31-generic, glibc 2.43)
2. Install Claude Code via VSCode extension (v2.1.270) or via:
sudo npm install -g @anthropic-ai/claude-code
3. Run `claude` in terminal, or open Claude Code panel in VSCode
4. Bun crashes with SIGSEGV or SIGABRT before any output/interaction
5. Behavior is intermittent — occasionally starts, usually crashes
6. Also reproduced inside a fresh Ubuntu 24.04 Docker container running
on the same host — same crash occurs

### Claude Model

None

### Is this a regression?

I don't know

### Last Working Version

_No response_

### Claude Code Version

2.1.270 (Claude Code)

### Platform

Anthropic API

### Operating System

Ubuntu/Debian Linux

### Terminal/Shell

VS Code integrated terminal

### Additional Information

- Bun version: 1.4.3
- Reproduced both via VSCode extension and standalone CLI (npm install)
- Reproduced inside Docker container (ubuntu:24.04) running on the same
host, suggesting the issue may relate to host kernel (7.0.0) rather
than purely glibc version in the container
- SMART health check on system disk: PASSED, no errors
- Basic RAM test (memtester, 1 pass, 2GB): no errors found
- This appears to be a very fresh combination (Ubuntu 26.04.1, glibc 2.43,
kernel 7.0.0) that may not yet be tested against Bun 1.4.3