diff --git a/src/libsodium/sodium/utils.c b/src/libsodium/sodium/utils.c
index 9d927eb1..287202a4 100644
--- a/src/libsodium/sodium/utils.c
+++ b/src/libsodium/sodium/utils.c
@@ -429,14 +429,14 @@ sodium_free(void *ptr)
         return;
     }
     canary_ptr = ((unsigned char *) ptr) - sizeof canary;
-    sodium_mprotect_readwrite(ptr);
-    if (sodium_memcmp(canary_ptr, canary, sizeof canary) != 0) {
-        _out_of_bounds();
-    }
     unprotected_ptr = _unprotected_ptr_from_user_ptr(ptr);
     base_ptr = unprotected_ptr - page_size * 2U;
     memcpy(&unprotected_size, base_ptr, sizeof unprotected_size);
     total_size = page_size + page_size + unprotected_size + page_size;
+    _mprotect_readwrite(base_ptr, total_size);
+    if (sodium_memcmp(canary_ptr, canary, sizeof canary) != 0) {
+        _out_of_bounds();
+    }
 #ifndef HAVE_PAGE_PROTECTION
     if (sodium_memcmp(unprotected_ptr + unprotected_size,
                       canary, sizeof canary) != 0) {