diff --git a/sample/sample-plugins/keying-material-exporter-demo/keyingmaterialexporter.c b/sample/sample-plugins/keying-material-exporter-demo/keyingmaterialexporter.c
index 44a8c027..c4839077 100644
--- a/sample/sample-plugins/keying-material-exporter-demo/keyingmaterialexporter.c
+++ b/sample/sample-plugins/keying-material-exporter-demo/keyingmaterialexporter.c
@@ -143,7 +143,7 @@ session_user_set(struct session *sess, X509 *x509)
             continue;
         }
         unsigned char *buf = NULL;
-        if (ASN1_STRING_to_UTF8(&buf, val) <= 0)
+        if (ASN1_STRING_to_UTF8(&buf, val) < 0)
         {
             continue;
         }
diff --git a/sample/sample-plugins/log/log_v3.c b/sample/sample-plugins/log/log_v3.c
index 12da624c..98d80d95 100644
--- a/sample/sample-plugins/log/log_v3.c
+++ b/sample/sample-plugins/log/log_v3.c
@@ -227,7 +227,7 @@ x509_print_info(X509 *x509crt)
         {
             continue;
         }
-        if (ASN1_STRING_to_UTF8(&buf, val) <= 0)
+        if (ASN1_STRING_to_UTF8(&buf, val) < 0)
         {
             continue;
         }