diff --git a/repos/base-hw/src/core/kernel/thread.cc b/repos/base-hw/src/core/kernel/thread.cc
index 64b94d0775..3651ec75ff 100644
--- a/repos/base-hw/src/core/kernel/thread.cc
+++ b/repos/base-hw/src/core/kernel/thread.cc
@@ -615,6 +615,9 @@ void Thread::print(Genode::Output &out) const
 }
 
 
+Genode::uint8_t __initial_stack_base[DEFAULT_STACK_SIZE];
+
+
 /*****************
  ** Core_thread **
  *****************/
@@ -624,7 +627,6 @@ Core_thread::Core_thread()
 {
 	using Genode::Native_utcb;
 
-	static Genode::uint8_t stack[DEFAULT_STACK_SIZE];
 	static Native_utcb * const utcb =
 		unmanaged_singleton<Native_utcb, Genode::get_page_size()>();
 
@@ -637,7 +639,7 @@ Core_thread::Core_thread()
 	utcb->cap_add(cap_id_invalid());
 
 	/* start thread with stack pointer at the top of stack */
-	sp = (addr_t)&stack + DEFAULT_STACK_SIZE;
+	sp = (addr_t)&__initial_stack_base[0] + DEFAULT_STACK_SIZE;
 	ip = (addr_t)&_core_start;
 
 	affinity(cpu_pool()->primary_cpu());
diff --git a/repos/base-hw/src/lib/startup/spec/riscv/crt0.s b/repos/base-hw/src/lib/startup/spec/riscv/crt0.s
index ab5915b61d..fd601b85da 100644
--- a/repos/base-hw/src/lib/startup/spec/riscv/crt0.s
+++ b/repos/base-hw/src/lib/startup/spec/riscv/crt0.s
@@ -36,5 +36,7 @@ _start:
 
 .bss
 	.p2align 8
-	.space 32*1024
+	.global __initial_stack_base
+	__initial_stack_base:
+	.space 4*1024
 	_stack_high:
diff --git a/repos/base/src/include/base/internal/crt0.h b/repos/base/src/include/base/internal/crt0.h
index b9f4bb2eec..711ce09619 100644
--- a/repos/base/src/include/base/internal/crt0.h
+++ b/repos/base/src/include/base/internal/crt0.h
@@ -28,8 +28,8 @@ extern void (*_dtors_start)();  /* begin of destructor table */
 extern void (*_dtors_end)();    /* end of destructor table */
 
 extern unsigned _start;         /* program entry point */
-extern unsigned _stack_low;     /* lower bound of intial stack */
-extern unsigned _stack_high;    /* upper bound of intial stack */
+
+extern unsigned char _initial_stack_base[];
 
 
 /***************************************************
diff --git a/repos/base/src/lib/startup/init_main_thread.cc b/repos/base/src/lib/startup/init_main_thread.cc
index 350d3971c0..4d714a52a4 100644
--- a/repos/base/src/lib/startup/init_main_thread.cc
+++ b/repos/base/src/lib/startup/init_main_thread.cc
@@ -40,6 +40,12 @@ enum { MAIN_THREAD_STACK_SIZE = 16UL * 1024 * sizeof(Genode::addr_t) };
 extern "C" void init_rtld() __attribute__((weak));
 void init_rtld() { }
 
+/**
+ * Lower bound of the stack, solely used for sanity checking
+ */
+extern unsigned char __initial_stack_base[];
+
+
 /**
  * The first thread in a program
  */
@@ -101,8 +107,24 @@ extern "C" void init_main_thread()
 	 * The new stack pointer enables the caller to switch from its current
 	 * environment to the those that the thread object provides.
 	 */
-	addr_t sp = reinterpret_cast<addr_t>(main_thread()->stack_top());
+	addr_t const sp = reinterpret_cast<addr_t>(main_thread()->stack_top());
 	init_main_thread_result = sp;
+
+	/*
+	 * Sanity check for the usage of the initial stack
+	 *
+	 * Because the initial stack is located in the BSS, it is zero-initialized.
+	 * We check that the stack still contains zeros at its lower boundary after
+	 * executing all the initialization code.
+	 */
+	enum { STACK_PAD = 256U };
+	for (unsigned i = 0; i < STACK_PAD; i++) {
+		if (__initial_stack_base[i] == 0)
+			continue;
+
+		error("initial stack overflow detected");
+		for (;;);
+	}
 }
 
 
diff --git a/repos/base/src/lib/startup/spec/arm/crt0.s b/repos/base/src/lib/startup/spec/arm/crt0.s
index 2444dea7ef..9f5bf8d244 100644
--- a/repos/base/src/lib/startup/spec/arm/crt0.s
+++ b/repos/base/src/lib/startup/spec/arm/crt0.s
@@ -57,7 +57,9 @@
 
 	/* stack of the temporary initial environment */
 	.p2align 4
-	.space 32 * 1024
+	.global __initial_stack_base
+	__initial_stack_base:
+	.space 4*1024
 	_stack_high:
 
 	/* initial value of the SP register */
diff --git a/repos/base/src/lib/startup/spec/x86_32/crt0.s b/repos/base/src/lib/startup/spec/x86_32/crt0.s
index fd37573cc4..a36855fcc4 100644
--- a/repos/base/src/lib/startup/spec/x86_32/crt0.s
+++ b/repos/base/src/lib/startup/spec/x86_32/crt0.s
@@ -90,7 +90,9 @@
 
 	/* stack of the temporary initial environment */
 	.p2align 4
-	.space 32 * 1024
+	.global __initial_stack_base
+	__initial_stack_base:
+	.space 4*1024
 	_stack_high:
 
 	/* initial value of the ESP, EAX and EDI register */
diff --git a/repos/base/src/lib/startup/spec/x86_64/crt0.s b/repos/base/src/lib/startup/spec/x86_64/crt0.s
index dc6a109065..4177a555a1 100644
--- a/repos/base/src/lib/startup/spec/x86_64/crt0.s
+++ b/repos/base/src/lib/startup/spec/x86_64/crt0.s
@@ -89,16 +89,18 @@
 
 	/* stack of the temporary initial environment */
 	.p2align 8
-	.space 32 * 1024
+	.global __initial_stack_base
+	__initial_stack_base:
+	.space 8*1024
 	_stack_high:
 
 	/* initial value of the RSP, RAX and RDI register */
-	.globl __initial_sp
+	.global __initial_sp
 	__initial_sp:
 	.space 8
-	.globl __initial_ax
+	.global __initial_ax
 	__initial_ax:
 	.space 8
-	.globl __initial_di
+	.global __initial_di
 	__initial_di:
 	.space 8