diff -pruN 1:9.11.19+dfsg-1/debian/changelog 1:9.11.19+dfsg-1ubuntu1/debian/changelog
--- 1:9.11.19+dfsg-1/debian/changelog	2020-05-19 20:19:50.000000000 +0000
+++ 1:9.11.19+dfsg-1ubuntu1/debian/changelog	2020-08-11 13:25:14.000000000 +0000
@@ -1,3 +1,11 @@
+bind9-libs (1:9.11.19+dfsg-1ubuntu1) groovy; urgency=medium
+
+  [ Jorge Niedbalski <jorge.niedbalski@canonical.com> ]
+  * debian/patches/0010-fix-1872118.patch: Check if pending_send
+    if set before calling dispatch_send. Fixes LP: #1872118.
+
+ -- Gianfranco Costamagna <locutusofborg@debian.org>  Tue, 11 Aug 2020 15:25:14 +0200
+
 bind9-libs (1:9.11.19+dfsg-1) unstable; urgency=medium
 
   * New upstream version 9.11.19+dfsg
diff -pruN 1:9.11.19+dfsg-1/debian/patches/0010-fix-1872118.patch 1:9.11.19+dfsg-1ubuntu1/debian/patches/0010-fix-1872118.patch
--- 1:9.11.19+dfsg-1/debian/patches/0010-fix-1872118.patch	1970-01-01 00:00:00.000000000 +0000
+++ 1:9.11.19+dfsg-1ubuntu1/debian/patches/0010-fix-1872118.patch	2020-08-11 13:25:08.000000000 +0000
@@ -0,0 +1,22 @@
+Description: Check if sock->pending_send is set
+before calling dispatch_send(). This would prevent
+the assertion failure in cases where a socket is not dead (closed)
+and its still pending to send data and the process_fd
+event gets triggered due a wakeup.
+
+Author: Jorge Niedbalski <jorge.niedbalski@canonical.com>
+Bug-Ubuntu: https://bugs.launchpad.net/bugs/1872118
+Forwarded: no
+Last-Update: 2020-08-03
+
+--- bind9-libs-9.11.16+dfsg.orig/lib/isc/unix/socket.c
++++ bind9-libs-9.11.16+dfsg/lib/isc/unix/socket.c
+@@ -4050,7 +4050,7 @@ check_write:
+ 		if (!SOCK_DEAD(sock)) {
+ 			if (sock->connecting)
+ 				dispatch_connect(sock);
+-			else
++			else if (!sock->pending_send)
+ 				dispatch_send(sock);
+ 		}
+ 		unwatch_write = true;
diff -pruN 1:9.11.19+dfsg-1/debian/patches/series 1:9.11.19+dfsg-1ubuntu1/debian/patches/series
--- 1:9.11.19+dfsg-1/debian/patches/series	2020-05-19 20:19:50.000000000 +0000
+++ 1:9.11.19+dfsg-1ubuntu1/debian/patches/series	2020-08-11 13:25:14.000000000 +0000
@@ -7,3 +7,4 @@
 0007-skip-rtld-deepbind-for-dyndb.diff
 0008-Use-absolute-srcdir-path-to-protoc-c-invocation.patch
 0009-python-fix-for-dist-packages.patch
+0010-fix-1872118.patch