diff --git a/CHANGELOG b/CHANGELOG
index 5eff0ee..b719df7 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -410,3 +410,7 @@
 * Update Synapse to 1.33.1
 * Fix bug where /sync would break if using the latest version of attrs dependency, by pinning to a previous version. (#9937)
 
+[1.23.2]
+* Update Synapse to 1.33.2
+* This release fixes a denial of service attack (CVE-2021-29471) against Synapse's push rules implementation.
+
diff --git a/CloudronManifest.json b/CloudronManifest.json
index 9961964..2122b02 100644
--- a/CloudronManifest.json
+++ b/CloudronManifest.json
@@ -5,7 +5,7 @@
   "description": "file://DESCRIPTION.md",
   "changelog": "file://CHANGELOG",
   "tagline": "Secure & decentralized communication",
-  "version": "1.23.1",
+  "version": "1.23.2",
   "healthCheckPath": "/",
   "httpPort": 8008,
   "memoryLimit": 536870912,
diff --git a/DESCRIPTION.md b/DESCRIPTION.md
index 10b48b1..8a8a00a 100644
--- a/DESCRIPTION.md
+++ b/DESCRIPTION.md
@@ -1,4 +1,4 @@
-This app packages Synapse <upstream>1.33.1</upstream>.
+This app packages Synapse <upstream>1.33.2</upstream>.
 
 **This package only provides the Matrix backend. A variety of clients are available
 [here](https://matrix.org/clients/). Riot is a popular web frontend for Matrix and
diff --git a/Dockerfile b/Dockerfile
index 551a744..5e940f9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,7 +9,7 @@ RUN virtualenv -p python3 /app/code/env
 ENV VIRTUAL_ENV=/app/code/env
 ENV PATH="$VIRTUAL_ENV/bin:$PATH"
 
-ARG VERSION=v1.33.1
+ARG VERSION=v1.33.2
 
 # Synapse (https://github.com/matrix-org/synapse/blob/master/INSTALL.md)
 # lxml - required for previews