diff --git a/core/include/thread.h b/core/include/thread.h
index 023626c9869f7..cfce0fea27eef 100644
--- a/core/include/thread.h
+++ b/core/include/thread.h
@@ -454,11 +454,13 @@ static inline const char *thread_getname(kernel_pid_t pid)
  *
  * Only works if the thread was created with the flag THREAD_CREATE_STACKTEST.
  *
- * @param[in] stack the stack you want to measure. Try `thread_get_stackstart(thread_get_active())`
+ * @param[in] stack     the stack you want to measure. Try
+ *                      `thread_get_stackstart(thread_get_active())`
+ * @param[in] size      size of @p stack in bytes
  *
- * @return          the amount of unused space of the thread's stack
+ * @return              the amount of unused space of the thread's stack
  */
-uintptr_t thread_measure_stack_free(const char *stack);
+uintptr_t thread_measure_stack_free(const char *stack, size_t size);
 
 /**
  * @brief   Get the number of bytes used on the ISR stack
diff --git a/core/thread.c b/core/thread.c
index 6ce6042e2dbf0..9bf523048caf2 100644
--- a/core/thread.c
+++ b/core/thread.c
@@ -171,15 +171,18 @@ void thread_add_to_list(list_node_t *list, thread_t *thread)
     list->next = new_node;
 }
 
-uintptr_t thread_measure_stack_free(const char *stack)
+uintptr_t thread_measure_stack_free(const char *stack, size_t size)
 {
     /* Alignment of stack has been fixed (if needed) by thread_create(), so
      * we can silence -Wcast-align here */
     uintptr_t *stackp = (uintptr_t *)(uintptr_t)stack;
+    uintptr_t end = (uintptr_t)stack + size;
+
+    /* better be safe than sorry: align end of stack just in case */
+    end &= (sizeof(uintptr_t) - 1);
 
-    /* assume that the comparison fails before or after end of stack */
     /* assume that the stack grows "downwards" */
-    while (*stackp == (uintptr_t)stackp) {
+    while (((uintptr_t)stackp < end) && (*stackp == (uintptr_t)stackp)) {
         stackp++;
     }
 
diff --git a/cpu/esp_common/freertos/task.c b/cpu/esp_common/freertos/task.c
index 2c3c8b12a59bc..16dac367daa45 100644
--- a/cpu/esp_common/freertos/task.c
+++ b/cpu/esp_common/freertos/task.c
@@ -197,7 +197,8 @@ UBaseType_t uxTaskGetStackHighWaterMark(TaskHandle_t xTask)
     thread_t *thread = thread_get((xTask == NULL) ? (uint32_t)thread_getpid()
                                                   : (uint32_t)xTask);
     assert(thread != NULL);
-    return thread_measure_stack_free(thread->stack_start);
+    return thread_measure_stack_free(thread_get_stacksize(thread),
+                                     thread_get_stacksize(thread));
 }
 
 void *pvTaskGetThreadLocalStoragePointer(TaskHandle_t xTaskToQuery,
diff --git a/cpu/esp_common/thread_arch.c b/cpu/esp_common/thread_arch.c
index d9bb7d4c37e0c..6a0382a4cfa35 100644
--- a/cpu/esp_common/thread_arch.c
+++ b/cpu/esp_common/thread_arch.c
@@ -92,10 +92,9 @@ void thread_isr_stack_init(void)
 
 int thread_isr_stack_usage(void)
 {
-    /* cppcheck-suppress comparePointers
-     * (reason: comes from ESP-SDK, so should be valid) */
-    return &port_IntStackTop - &port_IntStack -
-           thread_measure_stack_free((char*)&port_IntStack);
+    size_t stack_size = (uintptr_t)&port_IntStackTop - (uintptr_t)&port_IntStack;
+    return stack_size -
+           thread_measure_stack_free((char *)&port_IntStack, stack_size);
 }
 
 void *thread_isr_stack_pointer(void)
diff --git a/sys/ps/ps.c b/sys/ps/ps.c
index 5663bdd29dc1e..759857ea4a1fc 100644
--- a/sys/ps/ps.c
+++ b/sys/ps/ps.c
@@ -98,7 +98,7 @@ void ps(void)
 #ifdef DEVELHELP
             int stacksz = thread_get_stacksize(p);                          /* get stack size */
             overall_stacksz += stacksz;
-            int stack_free = thread_measure_stack_free(thread_get_stackstart(p));
+            int stack_free = thread_measure_stack_free(thread_get_stackstart(p), stacksz);
             stacksz -= stack_free;
             overall_used += stacksz;
 #endif
diff --git a/sys/test_utils/print_stack_usage/print_stack_usage.c b/sys/test_utils/print_stack_usage/print_stack_usage.c
index b4e8f7c7761ef..6181326553de1 100644
--- a/sys/test_utils/print_stack_usage/print_stack_usage.c
+++ b/sys/test_utils/print_stack_usage/print_stack_usage.c
@@ -34,7 +34,7 @@
 
 void print_stack_usage_metric(const char *name, void *stack, unsigned max_size)
 {
-    unsigned free = thread_measure_stack_free(stack);
+    unsigned free = thread_measure_stack_free(stack, max_size);
 
     if ((LOG_LEVEL >= LOG_INFO) &&
         (thread_get_stacksize(thread_get_active()) >= MIN_SIZE)) {