diff --git a/Include/internal/pycore_interp_structs.h b/Include/internal/pycore_interp_structs.h
index badc97808c6132..2124e76514f1af 100644
--- a/Include/internal/pycore_interp_structs.h
+++ b/Include/internal/pycore_interp_structs.h
@@ -769,6 +769,12 @@ struct _is {
      * and should be placed at the beginning. */
     struct _ceval_state ceval;
 
+    /* This structure is carefully allocated so that it's correctly aligned
+     * to avoid undefined behaviors during LOAD and STORE. The '_malloced'
+     * field stores the allocated pointer address that will later be freed.
+     */
+    void *_malloced;
+
     PyInterpreterState *next;
 
     int64_t id;
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-10-14-17-07-37.gh-issue-140067.ID2gOm.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-10-14-17-07-37.gh-issue-140067.ID2gOm.rst
deleted file mode 100644
index 3c5a828101d9a8..00000000000000
--- a/Misc/NEWS.d/next/Core_and_Builtins/2025-10-14-17-07-37.gh-issue-140067.ID2gOm.rst
+++ /dev/null
@@ -1 +0,0 @@
-Fix memory leak in sub-interpreter creation.
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index c519485c1cc74c..a73bfff340ce48 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -1469,14 +1469,14 @@ bytearray_removesuffix_impl(PyByteArrayObject *self, Py_buffer *suffix)
 /*[clinic input]
 bytearray.resize
     size: Py_ssize_t
-        New size to resize to..
+        New size to resize to.
     /
 Resize the internal buffer of bytearray to len.
 [clinic start generated code]*/
 
 static PyObject *
 bytearray_resize_impl(PyByteArrayObject *self, Py_ssize_t size)
-/*[clinic end generated code: output=f73524922990b2d9 input=75fd4d17c4aa47d3]*/
+/*[clinic end generated code: output=f73524922990b2d9 input=6c9a260ca7f72071]*/
 {
     Py_ssize_t start_size = PyByteArray_GET_SIZE(self);
     int result = PyByteArray_Resize((PyObject *)self, size);
diff --git a/Objects/clinic/bytearrayobject.c.h b/Objects/clinic/bytearrayobject.c.h
index ffb45ade11f6dc..6f13865177dde5 100644
--- a/Objects/clinic/bytearrayobject.c.h
+++ b/Objects/clinic/bytearrayobject.c.h
@@ -599,7 +599,7 @@ PyDoc_STRVAR(bytearray_resize__doc__,
 "Resize the internal buffer of bytearray to len.\n"
 "\n"
 "  size\n"
-"    New size to resize to..");
+"    New size to resize to.");
 
 #define BYTEARRAY_RESIZE_METHODDEF    \
     {"resize", (PyCFunction)bytearray_resize, METH_O, bytearray_resize__doc__},
@@ -1796,4 +1796,4 @@ bytearray_sizeof(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
     return bytearray_sizeof_impl((PyByteArrayObject *)self);
 }
-/*[clinic end generated code: output=be6d28193bc96a2c input=a9049054013a1b77]*/
+/*[clinic end generated code: output=fdfe41139c91e409 input=a9049054013a1b77]*/
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 9398bcb29c83e4..29233c1959c4d0 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -81,7 +81,7 @@ class object "PyObject *" "&PyBaseObject_Type"
 
 #define END_TYPE_DICT_LOCK() Py_END_CRITICAL_SECTION2()
 
-#ifdef Py_DEBUG
+#ifndef NDEBUG
 // Return true if the world is currently stopped.
 static bool
 types_world_is_stopped(void)
diff --git a/Python/pystate.c b/Python/pystate.c
index bf6e4e56e6df87..dbed609f29aa07 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -457,19 +457,16 @@ _PyInterpreterState_Enable(_PyRuntimeState *runtime)
 static PyInterpreterState *
 alloc_interpreter(void)
 {
-    // Aligned allocation for PyInterpreterState.
-    // the first word of the memory block is used to store
-    // the original pointer to be used later to free the memory.
     size_t alignment = _Alignof(PyInterpreterState);
-    size_t allocsize = sizeof(PyInterpreterState) + sizeof(void *) + alignment - 1;
+    size_t allocsize = sizeof(PyInterpreterState) + alignment - 1;
     void *mem = PyMem_RawCalloc(1, allocsize);
     if (mem == NULL) {
         return NULL;
     }
-    void *ptr = _Py_ALIGN_UP((char *)mem + sizeof(void *), alignment);
-    ((void **)ptr)[-1] = mem;
-    assert(_Py_IS_ALIGNED(ptr, alignment));
-    return ptr;
+    PyInterpreterState *interp = _Py_ALIGN_UP(mem, alignment);
+    assert(_Py_IS_ALIGNED(interp, alignment));
+    interp->_malloced = mem;
+    return interp;
 }
 
 static void
@@ -484,7 +481,7 @@ free_interpreter(PyInterpreterState *interp)
             interp->obmalloc = NULL;
         }
         assert(_Py_IS_ALIGNED(interp, _Alignof(PyInterpreterState)));
-        PyMem_RawFree(((void **)interp)[-1]);
+        PyMem_RawFree(interp->_malloced);
     }
 }