A vulnerability in the Linux kernel's x86 configuration allows a kernel panic when Rust code calls core::fmt::write() with FineIBT enabled. This occurs because core::fmt::rt::Argument::fmt() disables Control Flow Integrity (CFI), causing a Control Protection exception under FineIBT. The issue is addressed by making CFI_AUTO_DEFAULT depend on either Rust being disabled or Rust version 1.88 or higher, which fixes the incompatibility. Rust 1.88 is scheduled for release in June 2025 and is expected to resolve this problem.