diff -Nru fastd-18/debian/changelog fastd-18/debian/changelog
--- fastd-18/debian/changelog	2019-06-29 11:49:11.000000000 +0000
+++ fastd-18/debian/changelog	2020-10-28 12:06:13.000000000 +0000
@@ -1,3 +1,12 @@
+fastd (18-3ubuntu0.1) focal-security; urgency=medium
+
+  * SECURITY UPDATE: denial of service in receive.c
+    - debian/patches/CVE-2020-27638.patch: fix buffer leak when receiving
+      invalid packets.
+    - CVE-2020-27638
+
+ -- Emilia Torino <emilia.torino@canonical.com>  Wed, 28 Oct 2020 09:06:13 -0300
+
 fastd (18-3build1) eoan; urgency=medium
 
   * Rebuild against new libjson-c4.
diff -Nru fastd-18/debian/control fastd-18/debian/control
--- fastd-18/debian/control	2018-01-08 19:48:21.000000000 +0000
+++ fastd-18/debian/control	2020-10-28 12:06:13.000000000 +0000
@@ -1,7 +1,8 @@
 Source: fastd
 Section: net
 Priority: optional
-Maintainer: Matthias Schiffer <mschiffer@universe-factory.net>
+Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
+XSBC-Original-Maintainer: Matthias Schiffer <mschiffer@universe-factory.net>
 Uploaders: Haiko Helmholz <jo-travolti@t-online.de>
 Build-Depends: debhelper (>= 9), cmake (>= 2.8.7), bison (>= 2.5), pkg-config, libcap-dev, libuecc-dev (>= 6), libsodium-dev, libssl-dev, libjson-c-dev, dpkg-dev (>= 1.16.1~)
 Standards-Version: 4.1.3
diff -Nru fastd-18/debian/patches/CVE-2020-27638.patch fastd-18/debian/patches/CVE-2020-27638.patch
--- fastd-18/debian/patches/CVE-2020-27638.patch	1970-01-01 00:00:00.000000000 +0000
+++ fastd-18/debian/patches/CVE-2020-27638.patch	2020-10-28 12:00:16.000000000 +0000
@@ -0,0 +1,43 @@
+From: Matthias Schiffer <mschiffer@universe-factory.net>
+Date: Mon, 19 Oct 2020 21:08:16 +0200
+Subject: receive: fix buffer leak when receiving invalid packets
+
+For fastd versions before v20, this was just a memory leak (which could
+still be used for DoS, as it's remotely triggerable). With the new
+buffer management of fastd v20, this will trigger an assertion failure
+instead as soon as the buffer pool is empty.
+
+Origin: upstream, https://github.com/NeoRaider/fastd/commit/737925113363b6130879729cdff9ccc46c33eaea
+Bug-Debian: https://bugs.debian.org/972521
+---
+ src/receive.c | 10 ++++++++++
+ 1 file changed, 10 insertions(+)
+
+diff --git a/src/receive.c b/src/receive.c
+index 732d4a7..a3ecfe3 100644
+--- a/src/receive.c
++++ b/src/receive.c
+@@ -186,6 +186,11 @@ static inline void handle_socket_receive_known(fastd_socket_t *sock, const fastd
+ 
+ 	case PACKET_HANDSHAKE:
+ 		fastd_handshake_handle(sock, local_addr, remote_addr, peer, buffer);
++		break;
++
++	default:
++		fastd_buffer_free(buffer);
++		pr_debug("received packet with invalid type from %P[%I]", peer, remote_addr);
+ 	}
+ }
+ 
+@@ -211,6 +216,11 @@ static inline void handle_socket_receive_unknown(fastd_socket_t *sock, const fas
+ 
+ 	case PACKET_HANDSHAKE:
+ 		fastd_handshake_handle(sock, local_addr, remote_addr, NULL, buffer);
++		break;
++
++	default:
++		fastd_buffer_free(buffer);
++		pr_debug("received packet with invalid type from unknown address %I", remote_addr);
+ 	}
+ }
+ 
diff -Nru fastd-18/debian/patches/series fastd-18/debian/patches/series
--- fastd-18/debian/patches/series	1970-01-01 00:00:00.000000000 +0000
+++ fastd-18/debian/patches/series	2020-10-28 12:00:16.000000000 +0000
@@ -0,0 +1 @@
+CVE-2020-27638.patch