diff --git a/4ff4bd024a9b6e7973b76b186ce085c2ca669d3e.patch b/4ff4bd024a9b6e7973b76b186ce085c2ca669d3e.patch
new file mode 100644
index 0000000..8b7142a
--- /dev/null
+++ b/4ff4bd024a9b6e7973b76b186ce085c2ca669d3e.patch
@@ -0,0 +1,49 @@
+From 4ff4bd024a9b6e7973b76b186ce085c2ca669d3e Mon Sep 17 00:00:00 2001
+From: Aki Tuomi <aki.tuomi@dovecot.fi>
+Date: Thu, 24 May 2018 12:48:58 +0000
+Subject: [PATCH] acl: Fix return value of acl_attribute_get_acl
+
+If matching acl entry is not found, it must return 0
+and not 1 because it did not find anything.
+
+Fixes dsync: Panic: file mailbox-attribute.c: line 362 (mailbox_attribute_get_stream): assertion failed: (value_r->value != NULL || value_r->value_stream != NULL)
+
+Broken in 37c72fa0cd3f1d74d79b64afb3fb6da5ffd4fe3a
+
+Found by @dl8bh
+---
+ src/plugins/acl/acl-attributes.c | 10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+diff --git a/src/plugins/acl/acl-attributes.c b/src/plugins/acl/acl-attributes.c
+index 2499a30f9c..f0d3177de4 100644
+--- a/src/plugins/acl/acl-attributes.c
++++ b/src/plugins/acl/acl-attributes.c
+@@ -60,7 +60,7 @@ static int acl_attribute_get_acl(struct mailbox *box, const char *key,
+ 	struct acl_object_list_iter *iter;
+ 	struct acl_rights rights, wanted_rights;
+ 	const char *id;
+-	int ret;
++	int ret = 0;
+ 
+ 	i_zero(value_r);
+ 
+@@ -88,11 +88,17 @@ static int acl_attribute_get_acl(struct mailbox *box, const char *key,
+ 		    rights.id_type == wanted_rights.id_type &&
+ 		    null_strcmp(rights.identifier, wanted_rights.identifier) == 0) {
+ 			value_r->value = acl_rights_export(&rights);
++			ret = 1;
+ 			break;
+ 		}
+ 	}
+-	if ((ret = acl_object_list_deinit(&iter)) < 0)
++	/* the return value here cannot be used, because this function
++	   needs to return whether it actually matched something
++	   or not */
++	if (acl_object_list_deinit(&iter) < 0) {
+ 		mail_storage_set_internal_error(box->storage);
++		ret = -1;
++	}
+ 	return ret;
+ }
+ 
diff --git a/dovecot23.changes b/dovecot23.changes
index 6270e66..5a16e8b 100644
--- a/dovecot23.changes
+++ b/dovecot23.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Fri Jul 13 21:23:16 UTC 2018 - mrueckert@suse.de
+
+- added
+  https://github.com/dovecot/core/commit/4ff4bd024a9b6e7973b76b186ce085c2ca669d3e.patch
+
 -------------------------------------------------------------------
 Wed Jul 11 14:17:57 UTC 2018 - mrueckert@suse.de
 
diff --git a/dovecot23.spec b/dovecot23.spec
index 2b28d90..fc5e19b 100644
--- a/dovecot23.spec
+++ b/dovecot23.spec
@@ -136,6 +136,7 @@ Source11:       http://pigeonhole.dovecot.org/releases/%{dovecot_branch}/%{dovec
 Source12:       dovecot23.keyring
 Patch:          dovecot-2.3.0-dont_use_etc_ssl_certs.patch
 Patch1:         dovecot-2.3.0-better_ssl_defaults.patch
+Patch2:         https://github.com/dovecot/core/commit/4ff4bd024a9b6e7973b76b186ce085c2ca669d3e.patch
 Summary:        IMAP and POP3 Server Written Primarily with Security in Mind
 License:        BSD-3-Clause AND LGPL-2.1-or-later AND MIT
 Group:          Productivity/Networking/Email/Servers