WSL: 'Exec format error' for versions > 2.1.62, binary not executable

Environment

• OS: Windows 11 with WSL
• Shell: PowerShell → WSL bash
• Working version: 2.1.62
• Latest stable: 2.1.109
• Invocation: wsl claude

Problem

Any Claude Code version newer than 2.1.62 fails to execute in WSL with:

/bin/bash: line 1: /usr/bin/claude: cannot execute binary file: Exec format error

Version 2.1.62 works correctly under the same WSL environment.

Steps to Reproduce

1. Install Claude Code > 2.1.62 (e.g. 2.1.109) on WSL
2. Run wsl claude from PowerShell
3. Error: cannot execute binary file: Exec format error

Expected Behavior

Claude Code should execute normally, as it does on version 2.1.62.

Notes

Exec format error typically indicates an architecture mismatch (e.g. binary compiled for x86_64 but running on ARM, or wrong ELF format for the WSL kernel). Something changed in the build pipeline between 2.1.62 and 2.1.63+.