[BUG] Linux: Bun runtime segfault on Linux (claude-code 2.1.143, Bun 1.3.14, Ubuntu 24.04 / kernel 6.18.x)

Preflight Checklist

• [x] I have searched existing issues 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?

Bug: Bun runtime segfault on Linux (claude-code 2.1.143, Bun 1.3.14)

Claude Code crashes at least once a day with a Bun-level segfault. Bundled Bun panics before any JS handler can catch it, so --debug and stderr show only the Bun crash report. Happens during normal interactive sessions; no specific tool call reliably triggers it.

Environment

• Claude Code: 2.1.143
• Bun (bundled): 1.3.14 (d2989145) — baseline x86_64 build
• OS: Ubuntu 24.04.4 LTS (Noble), kernel 6.18.7-76061807-generic
• glibc: 2.39
• CPU features reported by Bun: sse42 popcnt avx avx2
• RSS at crash: 0.22 GB (peak 0.70 GB) on a 24.76 GB machine — not OOM.
• Elapsed before crash: ~9120 s (~2.5 h session)

Crash output
panic: Segmentation fault at address 0x22578AE5C60
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Illegal instruction (core dumped)

Notes

• Multiple BUN bug reports have also been filed - the latest at https://bun.report/1.3.14/B_1d298914mgkgkEuhogC4wvo4E+ypRg6rh8Cs+9v6C29gw6Cyj18zD+wmznEiroznEkhvynEysiynE0+n+hDy6zj8CmqlnB2muqCA2qiBgmu514D
• Not deterministic. Occurs mid-session after long-running use; no specific MCP server or tool consistently precedes it.
• I will be attempting to revert to Claude Code 2.1.112 as a workaround until this bug can be resolved.

Asks

1. Is the bundled Bun version pinnable, or planned to advance past 1.3.14?
2. Any way to capture a real core dump or stack from inside the bundled Bun for future crashes?
3. Known-good Claude Code version for Ubuntu 24.04 / kernel 6.18.x users while this is investigated.

What Should Happen?

Claude and Bun should not crash

Error Messages/Logs

Bun v1.3.14 (d2989145) Linux x64 (baseline)
Linux Kernel v6.18.7 | glibc v2.39
CPU: sse42 popcnt avx avx2end
Args: "claude"
Features: Bun.stderr(2) Bun.stdin(2) Bun.stdout(2) abort_signal(85) fetch(593) jsc spawn(132) standalone_executable process_dlopen yaml_parse(29) claude_code 
Builtins: "bun:main" "node:assert" "node:async_hooks" "node:buffer" "node:child_process" "node:constants" "node:crypto" "node:dns" "node:events" "node:fs" "node:fs/promises" "node:http" "node:https" "node:module" "node:net" "node:os" "node:path" "node:path/posix" "node:path/win32" "node:perf_hooks" "node:process" "node:readline" "node:stream" "node:stream/consumers" "node:stream/promises" "node:string_decoder" "node:timers/promises" "node:tls" "node:tty" "node:url" "node:util" "node:vm" "node:zlib" "ws" "node:http2" 
Elapsed: 9120252ms | User: 510522ms | Sys: 102347ms
RSS: 0.22GB | Peak: 0.70GB | Commit: 0.22GB | Faults: 0 | Machine: 24.76GB

panic: Segmentation fault at address 0x22578AE5C60
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

To send a redacted crash report to Bun's team,
please file a GitHub issue using the link below:

 https://bun.report/1.3.14/B_1d298914mgkgkEuhogC4wvo4E+ypRg6rh8Cs+9v6C29gw6Cyj18zD+wmznEiroznEkhvynEysiynE0+n+hDy6zj8CmqlnB2muqCA2qiBgmu514D

Illegal instruction (core dumped)

Steps to Reproduce

Apparently, the steps to reproduce is use Claude in a session at least 2 hours...

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.143

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_