Claude Code 2.1.243 segfaults on launch (CachyOS/glibc 2.44) — 2.1.241 unaffected

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?

Claude Code 2.1.243 segfaults immediately on every launch (confirmed with claude --version). The previous build, 2.1.241, runs fine on the same machine. Reverting the claude symlink to 2.1.241 resolves the crash.

What Should Happen?

Claude should start in shell but it get segfaults

Error Messages/Logs

Immediate SIGSEGV. Kernel log confirms a null-pointer dereference at the *same* instruction address across multiple independent runs:

claude[5563]: segfault at 0 ip 0000000001d10458 sp 00007ffded066fb0 error 4 in 2.1.243[1b0f458,1953000+3b33000] likely on CPU 1 (core 1, socket 0)
claude[5907]: segfault at 0 ip 0000000001d10458 sp 00007ffc7ace8360 error 4 in 2.1.243[1b0f458,1953000+3b33000] likely on CPU 7 (core 7, socket 0)
claude[5927]: segfault at 0 ip 0000000001d10458 sp 00007fff819e2e20 error 4 in 2.1.243[1b0f458,1953000+3b33000] likely on CPU 6 (core 6, socket 0)

The identical fault address (`ip 0x1d10458`) across independent runs indicates a deterministic bug in the 2.1.243 build itself, rather than memory corruption or a transient/hardware issue.

Steps to Reproduce

1. On CachyOS (Arch-based) with glibc 2.44, update Claude Code to 2.1.243.
2. Run claude --version (or any claude invocation).
3. Process segfaults immediately (exit code 139).

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Claude Code version affected: 2.1.243 (working version: 2.1.241)

Claude Code Version

Claude Code version affected: 2.1.243 (working version: 2.1.241)

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

Other

Additional Information

Environment

• Claude Code version affected: 2.1.243 (working version: 2.1.241)
• OS: CachyOS Linux (Arch-based), rolling
• Kernel: 7.2.0-1-cachyos #1 SMP PREEMPT_DYNAMIC
• glibc: 2.44
• CPU: AMD Ryzen 7 5800X3D 8-Core Processor
• Install method: native installer (binaries under ~/.local/share/claude/versions/, ~/.local/bin/claude symlinked to active version)