diff --git a/AK/ByteBuffer.h b/AK/ByteBuffer.h
index c0cbe0b2ba..ce160e32a3 100644
--- a/AK/ByteBuffer.h
+++ b/AK/ByteBuffer.h
@@ -214,7 +214,7 @@ public:
     {
         // make sure we're not told to write past the end
         VERIFY(offset + data_size <= size());
-        __builtin_memcpy(this->data() + offset, data, data_size);
+        __builtin_memmove(this->data() + offset, data, data_size);
     }
 
     void zero_fill()
diff --git a/AK/Span.h b/AK/Span.h
index 2de4af8da5..93e48bf911 100644
--- a/AK/Span.h
+++ b/AK/Span.h
@@ -144,7 +144,7 @@ public:
     {
         // make sure we're not told to write past the end
         VERIFY(offset + data_size <= size());
-        __builtin_memcpy(this->data() + offset, data, data_size);
+        __builtin_memmove(this->data() + offset, data, data_size);
     }
 
     ALWAYS_INLINE constexpr size_t copy_to(Span<RemoveConst<T>> other) const