[BUG] Claude Code 2.1.277 crashes on startup

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Claude Code 2.1.277 crashes on startup (claude --version, even with a fresh HOME) with panic: capacity overflow in bundled Bun v1.4.3. 2.1.267 works on the same machine. Env: Ubuntu VM in VirtualBox, Linux Kernel 7.0.0, glibc 2.39, x86_64 with avx/avx2, 4 GB RAM.
bun.report: https://bun.report/1.4.3/l_18c28b31kggggQggggCu90u0D09qs0D29ts0D0t800Dujpz0Dghpz0D6xs2rDmq7k8B26p8hCq2/x3Bow9vtC__ol+v5Dol+v5Dms+n5D0nzqsE815/2EwjhplCA0eNpLTixITM4sqVTIL0stSsvJLwcAPNYG4w

Post Edit:
Version 2.1.278 can't be launched, strace shows:

3469  ioctl(1, TCGETS, {c_iflag=ICRNL|IXON|IXOFF|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0
3469  rt_sigprocmask(SIG_UNBLOCK, [TTOU], NULL, 8) = 0
3469  rt_sigprocmask(SIG_BLOCK, [TTOU], NULL, 8) = 0
3469  ioctl(2, TCGETS, {c_iflag=ICRNL|IXON|IXOFF|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0
3469  ioctl(2, TCSETS, {c_iflag=ICRNL|IXON|IXOFF|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0
3469  ioctl(2, TCGETS, {c_iflag=ICRNL|IXON|IXOFF|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0
3469  rt_sigprocmask(SIG_UNBLOCK, [TTOU], NULL, 8) = 0
3469  rt_sigaction(SIGTERM, {sa_handler=SIG_DFL, sa_mask=[TERM], sa_flags=SA_RESTORER|SA_RESTART, sa_restorer=0x7b55d9845330}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER|SA_RESETHAND, sa_restorer=0x7b55d9845330}, 8) = 0
3469  gettid()                          = 3469
3469  getpid()                          = 3469
3469  tgkill(3469, 3469, SIGTERM)       = 0
3469  rt_sigreturn({mask=[]})           = -1 EINTR (Unterbrechung während des Betriebssystemaufrufs)
3469  --- SIGTERM {si_signo=SIGTERM, si_code=SI_TKILL, si_pid=3469, si_uid=1000} ---
3469  +++ killed by SIGTERM +++

What Should Happen?

Claude should start.

Error Messages/Logs

see description

Steps to Reproduce

run claude --version with 2.1.277 → crashes after ~6 ms.
Also crashes with a fresh HOME (HOME=$(mktemp -d) claude --version),
so it's not a config/state problem.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.267

Claude Code Version

2.1.277

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Xterm

Additional Information

• Auto-updated to 2.1.277 on Sep 18 (binary is 234 MB vs. 217 MB for 2.1.267)
• Switching the symlink back to 2.1.267 fixes it immediately
• CPU has avx/avx2, so not the known no-AVX crash
• 3.8 GB RAM, 197 GB disk (20% used), stack ulimit 8192, no unusual ulimits
• VirtualBox version: Version 7.2.10 r174163 (Qt6.8.0 on windows)

Reproduce the crash with claude --version on the described Ubuntu/Debian Linux VM, including a fresh HOME, and inspect the linked Bun 1.4.3 report first. Compare Claude Code 2.1.277 with the last working 2.1.267; done means Claude starts successfully and claude --version no longer reports the capacity-overflow panic.