diff --git a/SOURCES/bind99-assertfix.patch b/SOURCES/bind99-assertfix.patch
new file mode 100644
index 0000000..48572bb
--- /dev/null
+++ b/SOURCES/bind99-assertfix.patch
@@ -0,0 +1,30 @@
+From 4daf6b361203f17f2bba43f9c52eeccc698a0c52 Mon Sep 17 00:00:00 2001
+From: Pablo Greco <pablo@fliagreco.com.ar>
+Date: Wed, 12 Dec 2018 16:53:10 +0000
+Subject: [PATCH] Check buffer size before adding comment
+
+---
+ lib/dns/masterdump.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/lib/dns/masterdump.c b/lib/dns/masterdump.c
+index 80fcd4c..8e3f9e3 100644
+--- a/lib/dns/masterdump.c
++++ b/lib/dns/masterdump.c
+@@ -451,7 +451,13 @@ rdataset_totext(dns_rdataset_t *rdataset,
+ 		 * Comment?
+ 		 */
+ 		if ((ctx->style.flags & DNS_STYLEFLAG_COMMENTDATA) != 0)
++		{
++			isc_region_t r;
++			isc_buffer_availableregion(target, &r);
++			if (r.length < 1)
++				return (ISC_R_NOSPACE);
+ 			isc_buffer_putstr(target, ";");
++		}
+ 
+ 		/*
+ 		 * Owner name.
+-- 
+1.8.3.1
+