diff --git a/Documentation/reference/user/01_task_control.rst b/Documentation/reference/user/01_task_control.rst
index 60d22a0288d..e673d712776 100644
--- a/Documentation/reference/user/01_task_control.rst
+++ b/Documentation/reference/user/01_task_control.rst
@@ -358,7 +358,9 @@ Functions
      NOTE: ``vfork()`` is not an independent NuttX feature, but is
      implemented in architecture-specific logic (using only helper
      functions from the NuttX core logic). As a result, ``vfork()`` may
-     not be available on all architectures.
+     not be available on all architectures. The current implementation in
+     NuttX arm64 only guarantees that ``vfork()`` works when
+     CONFIG_BUILD_FLAT=y.
 
   :return: Upon successful completion, ``vfork()`` returns 0 to
     the child process and returns the process ID of the child process to the
diff --git a/arch/Kconfig b/arch/Kconfig
index e54b8a128a4..0ddcdb50c40 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -29,7 +29,7 @@ config ARCH_ARM64
 	select ARCH_64BIT
 	select ARCH_HAVE_BACKTRACE
 	select ARCH_HAVE_INTERRUPTSTACK
-	select ARCH_HAVE_FORK if !BUILD_KERNEL
+	select ARCH_HAVE_FORK if !BUILD_KERNEL && !BUILD_PROTECTED
 	select ARCH_HAVE_STACKCHECK
 	select ARCH_HAVE_CUSTOMOPT
 	select ARCH_HAVE_STDARG_H