diff -Nru avahi-0.7/debian/changelog avahi-0.7/debian/changelog
--- avahi-0.7/debian/changelog	2021-07-06 15:39:14.000000000 +0000
+++ avahi-0.7/debian/changelog	2023-05-31 13:59:47.000000000 +0000
@@ -1,3 +1,12 @@
+avahi (0.7-4ubuntu7.2) focal-security; urgency=medium
+
+  * SECURITY UPDATE: avahi-daemon can be crashed via DBus
+    - debian/patches/CVE-2023-1981.patch: emit error if requested service
+      is not found in avahi-daemon/dbus-protocol.c.
+    - CVE-2023-1981
+
+ -- Marc Deslauriers <marc.deslauriers@ubuntu.com>  Wed, 31 May 2023 09:59:47 -0400
+
 avahi (0.7-4ubuntu7.1) focal-security; urgency=medium
 
   * SECURITY UPDATE: DoS via infinite loop on local socket
diff -Nru avahi-0.7/debian/patches/CVE-2023-1981.patch avahi-0.7/debian/patches/CVE-2023-1981.patch
--- avahi-0.7/debian/patches/CVE-2023-1981.patch	1970-01-01 00:00:00.000000000 +0000
+++ avahi-0.7/debian/patches/CVE-2023-1981.patch	2023-05-31 13:59:40.000000000 +0000
@@ -0,0 +1,55 @@
+Backport of:
+
+From a2696da2f2c50ac43b6c4903f72290d5c3fa9f6f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
+Date: Thu, 17 Nov 2022 01:51:53 +0100
+Subject: [PATCH] Emit error if requested service is not found
+
+It currently just crashes instead of replying with error. Check return
+value and emit error instead of passing NULL pointer to reply.
+
+Fixes #375
+---
+ avahi-daemon/dbus-protocol.c | 20 ++++++++++++++------
+ 1 file changed, 14 insertions(+), 6 deletions(-)
+
+--- a/avahi-daemon/dbus-protocol.c
++++ b/avahi-daemon/dbus-protocol.c
+@@ -391,10 +391,14 @@ static DBusHandlerResult msg_server_impl
+         }
+ 
+         t = avahi_alternative_host_name(n);
+-        avahi_dbus_respond_string(c, m, t);
+-        avahi_free(t);
+-
+-        return DBUS_HANDLER_RESULT_HANDLED;
++        if (t) {
++            avahi_dbus_respond_string(c, m, t);
++            avahi_free(t);
++
++            return DBUS_HANDLER_RESULT_HANDLED;
++        } else {
++            return avahi_dbus_respond_error(c, m, AVAHI_ERR_NOT_FOUND, "Hostname not found");
++        }
+ 
+     } else if (dbus_message_is_method_call(m, AVAHI_DBUS_INTERFACE_SERVER, "GetAlternativeServiceName")) {
+         char *n, *t;
+@@ -405,10 +409,14 @@ static DBusHandlerResult msg_server_impl
+         }
+ 
+         t = avahi_alternative_service_name(n);
+-        avahi_dbus_respond_string(c, m, t);
+-        avahi_free(t);
+-
+-        return DBUS_HANDLER_RESULT_HANDLED;
++        if (t) {
++            avahi_dbus_respond_string(c, m, t);
++            avahi_free(t);
++
++            return DBUS_HANDLER_RESULT_HANDLED;
++        } else {
++            return avahi_dbus_respond_error(c, m, AVAHI_ERR_NOT_FOUND, "Service not found");
++        }
+ 
+     } else if (dbus_message_is_method_call(m, AVAHI_DBUS_INTERFACE_SERVER, "EntryGroupNew")) {
+         Client *client;
diff -Nru avahi-0.7/debian/patches/series avahi-0.7/debian/patches/series
--- avahi-0.7/debian/patches/series	2021-07-06 15:39:10.000000000 +0000
+++ avahi-0.7/debian/patches/series	2023-05-31 13:57:30.000000000 +0000
@@ -6,3 +6,4 @@
 local-only-services-support.patch
 CVE-2017-6519-and-CVE-2018-1000845.patch
 CVE-2021-3468.patch
+CVE-2023-1981.patch