diff -Naur a/crypto/x509v3/pcy_local.h b/crypto/x509v3/pcy_local.h
--- a/crypto/x509v3/pcy_local.h	2023-06-08 17:55:38.806638491 +0800
+++ b/crypto/x509v3/pcy_local.h	2023-06-08 17:51:40.695932010 +0800
@@ -111,6 +111,11 @@
 };
 
 struct X509_POLICY_TREE_st {
+    /* The number of nodes in the tree */
+    size_t node_count;
+    /* The maximum number of nodes in the tree */
+    size_t node_maximum;
+
     /* This is the tree 'level' data */
     X509_POLICY_LEVEL *levels;
     int nlevel;
@@ -159,7 +164,8 @@
 X509_POLICY_NODE *level_add_node(X509_POLICY_LEVEL *level,
                                  X509_POLICY_DATA *data,
                                  X509_POLICY_NODE *parent,
-                                 X509_POLICY_TREE *tree);
+                                 X509_POLICY_TREE *tree,
+                                 int extra_data);
 void policy_node_free(X509_POLICY_NODE *node);
 int policy_node_match(const X509_POLICY_LEVEL *lvl,
                       const X509_POLICY_NODE *node, const ASN1_OBJECT *oid);
diff -Naur a/crypto/x509v3/pcy_node.c b/crypto/x509v3/pcy_node.c
--- a/crypto/x509v3/pcy_node.c	2023-06-08 16:33:09.518582549 +0800
+++ b/crypto/x509v3/pcy_node.c	2023-06-08 17:41:44.829164303 +0800
@@ -59,10 +59,15 @@
 X509_POLICY_NODE *level_add_node(X509_POLICY_LEVEL *level,
                                  X509_POLICY_DATA *data,
                                  X509_POLICY_NODE *parent,
-                                 X509_POLICY_TREE *tree)
+                                 X509_POLICY_TREE *tree,
+                                 int extra_data)
 {
     X509_POLICY_NODE *node;
 
+    /* Verify that the tree isn't too large.  This mitigates CVE-2023-0464 */
+    if (tree->node_maximum > 0 && tree->node_count >= tree->node_maximum)
+        return NULL;
+
     node = OPENSSL_zalloc(sizeof(*node));
     if (node == NULL) {
         X509V3err(X509V3_F_LEVEL_ADD_NODE, ERR_R_MALLOC_FAILURE);
@@ -70,7 +75,7 @@
     }
     node->data = data;
     node->parent = parent;
-    if (level) {
+    if (level != NULL) {
         if (OBJ_obj2nid(data->valid_policy) == NID_any_policy) {
             if (level->anyPolicy)
                 goto node_error;
@@ -90,24 +95,33 @@
         }
     }
 
-    if (tree) {
+    if (extra_data) {
         if (tree->extra_data == NULL)
             tree->extra_data = sk_X509_POLICY_DATA_new_null();
         if (tree->extra_data == NULL){
             X509V3err(X509V3_F_LEVEL_ADD_NODE, ERR_R_MALLOC_FAILURE);
-            goto node_error;
+            goto extra_data_error;
         }
         if (!sk_X509_POLICY_DATA_push(tree->extra_data, data)) {
             X509V3err(X509V3_F_LEVEL_ADD_NODE, ERR_R_MALLOC_FAILURE);
-            goto node_error;
+            goto extra_data_error;
         }
     }
 
+    tree->node_count++;
     if (parent)
         parent->nchild++;
 
     return node;
 
+    extra_data_error:
+    if (level != NULL) {
+        if (level->anyPolicy == node)
+            level->anyPolicy = NULL;
+        else
+            (void) sk_X509_POLICY_NODE_pop(level->nodes);
+    }
+
  node_error:
     policy_node_free(node);
     return NULL;
diff -Naur a/crypto/x509v3/pcy_tree.c b/crypto/x509v3/pcy_tree.c
--- a/crypto/x509v3/pcy_tree.c	2023-06-08 16:33:09.518582549 +0800
+++ b/crypto/x509v3/pcy_tree.c	2023-06-08 17:47:21.872994766 +0800
@@ -14,6 +14,20 @@
 #include "pcy_local.h"
 
 /*
+ * If the maximum number of nodes in the policy tree isn't defined, set it to
+ * a generous default of 1000 nodes.
+ *
+ * Defining this to be zero means unlimited policy tree growth which opens the
+ * door on CVE-2023-0464.
+ */
+
+#ifndef OPENSSL_POLICY_TREE_NODES_MAX
+# define OPENSSL_POLICY_TREE_NODES_MAX 1000
+#endif
+
+static void exnode_free(X509_POLICY_NODE *node);
+
+/*
  * Enable this to print out the complete policy tree at various point during
  * evaluation.
  */
@@ -168,6 +182,9 @@
         return X509_PCY_TREE_INTERNAL;
     }
 
+    /* Limit the growth of the tree to mitigate CVE-2023-0464 */
+    tree->node_maximum = OPENSSL_POLICY_TREE_NODES_MAX;
+
     /*
      * http://tools.ietf.org/html/rfc5280#section-6.1.2, figure 3.
      *
@@ -184,7 +201,7 @@
     level = tree->levels;
     if ((data = policy_data_new(NULL, OBJ_nid2obj(NID_any_policy), 0)) == NULL)
         goto bad_tree;
-    if (level_add_node(level, data, NULL, tree) == NULL) {
+    if (level_add_node(level, data, NULL, tree, 1) == NULL) {
         policy_data_free(data);
         goto bad_tree;
     }
@@ -243,7 +260,8 @@
  * Return value: 1 on success, 0 otherwise
  */
 static int tree_link_matching_nodes(X509_POLICY_LEVEL *curr,
-                                    X509_POLICY_DATA *data)
+                                    X509_POLICY_DATA *data,
+                                    X509_POLICY_TREE *tree)
 {
     X509_POLICY_LEVEL *last = curr - 1;
     int i, matched = 0;
@@ -253,13 +271,13 @@
         X509_POLICY_NODE *node = sk_X509_POLICY_NODE_value(last->nodes, i);
 
         if (policy_node_match(last, node, data->valid_policy)) {
-            if (level_add_node(curr, data, node, NULL) == NULL)
+            if (level_add_node(curr, data, node, tree, 0) == NULL)
                 return 0;
             matched = 1;
         }
     }
     if (!matched && last->anyPolicy) {
-        if (level_add_node(curr, data, last->anyPolicy, NULL) == NULL)
+        if (level_add_node(curr, data, last->anyPolicy, tree, 0) == NULL)
             return 0;
     }
     return 1;
@@ -272,7 +290,8 @@
  * Return value: 1 on success, 0 otherwise.
  */
 static int tree_link_nodes(X509_POLICY_LEVEL *curr,
-                           const X509_POLICY_CACHE *cache)
+                           const X509_POLICY_CACHE *cache,
+                           X509_POLICY_TREE *tree)
 {
     int i;
 
@@ -280,7 +299,7 @@
         X509_POLICY_DATA *data = sk_X509_POLICY_DATA_value(cache->data, i);
 
         /* Look for matching nodes in previous level */
-        if (!tree_link_matching_nodes(curr, data))
+        if (!tree_link_matching_nodes(curr, data, tree))
             return 0;
     }
     return 1;
@@ -311,7 +330,7 @@
     /* Curr may not have anyPolicy */
     data->qualifier_set = cache->anyPolicy->qualifier_set;
     data->flags |= POLICY_DATA_FLAG_SHARED_QUALIFIERS;
-    if (level_add_node(curr, data, node, tree) == NULL) {
+    if (level_add_node(curr, data, node, tree, 1) == NULL) {
         policy_data_free(data);
         return 0;
     }
@@ -373,7 +392,7 @@
     }
     /* Finally add link to anyPolicy */
     if (last->anyPolicy &&
-        level_add_node(curr, cache->anyPolicy, last->anyPolicy, NULL) == NULL)
+        level_add_node(curr, cache->anyPolicy, last->anyPolicy, tree, 0) == NULL)
         return 0;
     return 1;
 }
@@ -555,15 +574,24 @@
             extra->qualifier_set = anyPolicy->data->qualifier_set;
             extra->flags = POLICY_DATA_FLAG_SHARED_QUALIFIERS
                 | POLICY_DATA_FLAG_EXTRA_NODE;
-            node = level_add_node(NULL, extra, anyPolicy->parent, tree);
+	    node = level_add_node(NULL, extra, anyPolicy->parent,
+                                  tree, 1);
+            if (node == NULL) {
+                policy_data_free(extra);
+                return 0;
+            }
         }
         if (!tree->user_policies) {
             tree->user_policies = sk_X509_POLICY_NODE_new_null();
-            if (!tree->user_policies)
-                return 1;
+	    if (!tree->user_policies) {
+                exnode_free(node);
+                return 0;
+            }
         }
-        if (!sk_X509_POLICY_NODE_push(tree->user_policies, node))
+        if (!sk_X509_POLICY_NODE_push(tree->user_policies, node)){
+	         exnode_free(node);
             return 0;
+	}
     }
     return 1;
 }
@@ -582,7 +610,7 @@
 
     for (i = 1; i < tree->nlevel; i++, curr++) {
         cache = policy_cache_set(curr->cert);
-        if (!tree_link_nodes(curr, cache))
+        if (!tree_link_nodes(curr, cache, tree))
             return X509_PCY_TREE_INTERNAL;
 
         if (!(curr->flags & X509_V_FLAG_INHIBIT_ANY)