MFV: crypto/openssl: update to 3.5.6

This change brings in version 3.5.6 of OpenSSL, which features
several security fixes (the highest of which is a MEDIUM severity
issue), as well as some miscellaneous feature updates.

Please see the release notes [1] for more details.

PS Apologies for the confusing merge commits -- I was testing out a
new automated update process and failed to catch the commit message
issues until after I pushed the change.

1. https://github.com/openssl/openssl/blob/openssl-3.5.6/NEWS.md

MFC after:	1 day (the security issues warrant a quick backport).
Merge commit 'ab5fc4ac933ff67bc800e774dffce15e2a541e90'

(cherry picked from commit 10a428653ee7216475f1ddce3fb4cbf1200319f8)

1 files changed, 6 insertions, 2 deletions

diff --git a/crypto/openssl/ssl/statem/statem_dtls.c b/crypto/openssl/ssl/statem/statem_dtls.c
index 4052ef6219b8..f62b757721fc 100644
--- a/crypto/openssl/ssl/statem/statem_dtls.c
+++ b/crypto/openssl/ssl/statem/statem_dtls.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2005-2025 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2005-2026 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -1177,7 +1177,11 @@ int dtls1_buffer_message(SSL_CONNECTION *s, int is_ccs)
         return 0;
     }
 
-    pqueue_insert(s->d1->sent_messages, item);
+    if (pqueue_insert(s->d1->sent_messages, item) == NULL) {
+        dtls1_hm_fragment_free(frag);
+        pitem_free(item);
+        return 0;
+    }
     return 1;
 }