## Summary
- Reject null bytes in command-line arguments passed to `Bun.spawn` and
`Bun.spawnSync`
- Reject null bytes in environment variable keys and values
- Reject null bytes in shell (`$`) template literal arguments
This prevents null byte injection attacks (CWE-158) where null bytes in
strings could cause unintended truncation when passed to the OS,
potentially allowing attackers to bypass file extension validation or
create files with unexpected names.
## Test plan
- [x] Added tests in `test/js/bun/spawn/null-byte-injection.test.ts`
- [x] Tests pass with debug build: `bun bd test
test/js/bun/spawn/null-byte-injection.test.ts`
- [x] Tests fail with system Bun (confirming the fix works)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
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