diff --git a/CHANGES/1229.bugfix.rst b/CHANGES/1229.bugfix.rst
new file mode 100644
index 000000000..a8ba7a4a7
--- /dev/null
+++ b/CHANGES/1229.bugfix.rst
@@ -0,0 +1 @@
+Fixed inconsistencies generated by the C implementation of ``_md_shrink()`` which might later lead to assertion failures and crash -- by :user:`Romain-Geissler-1A`.
diff --git a/multidict/_multilib/hashtable.h b/multidict/_multilib/hashtable.h
index 0e0a28e50..16b82ded1 100644
--- a/multidict/_multilib/hashtable.h
+++ b/multidict/_multilib/hashtable.h
@@ -261,6 +261,7 @@ _md_shrink(MultiDictObject *md, bool update)
     keys->nentries = newnentries;
     keys->usable += nentries - newnentries;
     memset(&keys->indices[0], 0xff, ((size_t)1 << keys->log2_index_bytes));
+    memset(new_ep, 0, sizeof(entry_t) * (size_t)(nentries - newnentries));
     if (htkeys_build_indices(keys, entries, newnentries, update) < 0) {
         return -1;
     }