diff -Nru python-oslo.privsep-2.1.1/debian/changelog python-oslo.privsep-2.1.1/debian/changelog
--- python-oslo.privsep-2.1.1/debian/changelog	2020-04-09 19:47:38.000000000 +0100
+++ python-oslo.privsep-2.1.1/debian/changelog	2023-08-04 14:56:14.000000000 +0100
@@ -1,3 +1,10 @@
+python-oslo.privsep (2.1.1-0ubuntu2) focal; urgency=medium
+
+  * Backport max_buffer_size fix (LP: #2029952)
+    - d/p/Bump-max_buffer_size-for-Deserializer.patch
+
+ -- Edward Hope-Morley <edward.hope-morley@canonical.com>  Fri, 04 Aug 2023 14:56:14 +0100
+
 python-oslo.privsep (2.1.1-0ubuntu1) focal; urgency=medium
 
   * New upstream release for OpenStack Ussuri.
diff -Nru python-oslo.privsep-2.1.1/debian/patches/Bump-max_buffer_size-for-Deserializer.patch python-oslo.privsep-2.1.1/debian/patches/Bump-max_buffer_size-for-Deserializer.patch
--- python-oslo.privsep-2.1.1/debian/patches/Bump-max_buffer_size-for-Deserializer.patch	1970-01-01 01:00:00.000000000 +0100
+++ python-oslo.privsep-2.1.1/debian/patches/Bump-max_buffer_size-for-Deserializer.patch	2023-08-04 14:56:05.000000000 +0100
@@ -0,0 +1,56 @@
+From c223dbced7d5a8d1920fe764cbce42cf844538e1 Mon Sep 17 00:00:00 2001
+From: Mohammed Naser <mnaser@vexxhost.com>
+Date: Wed, 1 Dec 2021 11:19:26 +0400
+Subject: [PATCH] Bump max_buffer_size for Deserializer
+
+Since msgpack 0.6.0, some limits were introduced for the
+deserializer which were put in to avoid any denial of service
+attacks using msgpack.  These limits were raised to 100MiB
+in the release of msgpack 1.0.0.
+
+The default buffer sizes that were implemented were quite low
+and when running certain `privsep` commands, especially for
+Neutron when using linux bridge, where there is a large amount
+of netdevs, privsep would crash since msgpack would fail to
+decode the message since it considers it too big:
+
+  ValueError: 1174941 exceeds max_str_len(1048576)
+
+In this commit, the `max_buffer_size` is bumped to the value
+that ships with msgpack==1.0.0 to allow for users who don't
+have that to continue to function. Also, since `msgpack` is
+only being used by the internal API, we're not worried about
+a third party coming in and overwhelming the system by
+deserializing calls.
+
+This fix also addresses some weird behaviour where privsep
+will die and certain OpenStack agents would start to behave
+in a strange way once they hit a certain number of ports (since
+any privsep calls would start to fail).
+
+Closes-Bug: #1844822
+Closes-Bug: #1896734
+Related-Bug: #1928764
+Closes-Bug: #1952611
+Change-Id: I135917522daff95377d07566317ef0fc0d16e7cb
+---
+ oslo_privsep/comm.py | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/oslo_privsep/comm.py b/oslo_privsep/comm.py
+index c609a87..9de82b4 100644
+--- a/oslo_privsep/comm.py
++++ b/oslo_privsep/comm.py
+@@ -72,7 +72,8 @@ class Deserializer(six.Iterator):
+         self.readsock = readsock
+         self.unpacker = msgpack.Unpacker(use_list=False, raw=False,
+                                          strict_map_key=False,
+-                                         unicode_errors='surrogateescape')
++                                         unicode_errors='surrogateescape',
++                                         max_buffer_size=100 * 1024 * 1024)
+ 
+     def __iter__(self):
+         return self
+-- 
+2.34.1
+
diff -Nru python-oslo.privsep-2.1.1/debian/patches/series python-oslo.privsep-2.1.1/debian/patches/series
--- python-oslo.privsep-2.1.1/debian/patches/series	1970-01-01 01:00:00.000000000 +0100
+++ python-oslo.privsep-2.1.1/debian/patches/series	2023-08-04 14:56:05.000000000 +0100
@@ -0,0 +1 @@
+Bump-max_buffer_size-for-Deserializer.patch