CVE-2026-64082

In the Linux kernel, the following vulnerability has been resolved:

riscv: Fix register corruption from uninitialized cregs on error

compat_riscv_gpr_set() calls cregs_to_regs() unconditionally, even when

user_regset_copyin() fails. Since cregs is an uninitialized stack

variable, a copyin failure causes uninitialized stack data to be written

into the target task's pt_regs, corrupting its register state and

potentially leaking kernel stack contents.

compat_restore_sigcontext() has the same issue: it calls cregs_to_regs()

even when __copy_from_user() fails, leading to the same corruption of

the signal-returning task's register state on error.

Only call cregs_to_regs() when the user copy succeeds.