diff --git a/CHANGES.md b/CHANGES.md
index e286dc1547..a4c686502d 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,15 @@
+# Synapse 1.139.1 (2025-10-07)
+
+## Security Fixes
+
+- Fix [CVE-2025-61672](https://www.cve.org/CVERecord?id=CVE-2025-61672) / [GHSA-fh66-fcv5-jjfr](https://github.com/element-hq/synapse/security/advisories/GHSA-fh66-fcv5-jjfr). Lack of validation for device keys in Synapse before 1.139.1 allows an attacker registered on the victim homeserver to degrade federation functionality, unpredictably breaking outbound federation to other homeservers. ([\#17097](https://github.com/element-hq/synapse/issues/17097))
+
+## Deprecations and Removals
+
+- Drop support for unstable field names from the long-accepted [MSC2732](https://github.com/matrix-org/matrix-spec-proposals/pull/2732) (Olm fallback keys) proposal. This change allows unit tests to pass following the security patch above. ([\#18996](https://github.com/element-hq/synapse/issues/18996))
+
+
+
 # Synapse 1.139.0 (2025-09-30)
 
 ### `/register` requests from old application service implementations may break when using MAS
diff --git a/debian/changelog b/debian/changelog
index c4450e0f52..1e128df6c0 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.139.1) stable; urgency=medium
+
+  * New Synapse release 1.139.1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Tue, 07 Oct 2025 11:46:51 +0100
+
 matrix-synapse-py3 (1.139.0) stable; urgency=medium
 
   * New Synapse release 1.139.0.
diff --git a/pyproject.toml b/pyproject.toml
index a79c19ae90..df4333f018 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -101,7 +101,7 @@ module-name = "synapse.synapse_rust"
 
 [tool.poetry]
 name = "matrix-synapse"
-version = "1.139.0"
+version = "1.139.1"
 description = "Homeserver for the Matrix decentralised comms protocol"
 authors = ["Matrix.org Team and Contributors <packages@matrix.org>"]
 license = "AGPL-3.0-or-later OR LicenseRef-Element-Commercial"