diff --git a/docs/releases.rst b/docs/releases.rst
index 8a0fad4c..5c7a106d 100644
--- a/docs/releases.rst
+++ b/docs/releases.rst
@@ -4,6 +4,7 @@ Release notes
 .. toctree::
    :maxdepth: 2
 
+   releases/v6.4.2
    releases/v6.4.1
    releases/v6.4.0
    releases/v6.3.3
diff --git a/docs/releases/v6.4.2.rst b/docs/releases/v6.4.2.rst
new file mode 100644
index 00000000..0dc567d1
--- /dev/null
+++ b/docs/releases/v6.4.2.rst
@@ -0,0 +1,12 @@
+What's new in Tornado 6.4.2
+===========================
+
+Nov 21, 2024
+------------
+
+Security Improvements
+~~~~~~~~~~~~~~~~~~~~~
+
+- Parsing of the cookie header is now much more efficient. The older algorithm sometimes had
+  quadratic performance which allowed for a denial-of-service attack in which the server would spend
+  excessive CPU time parsing cookies and block the event loop. This change fixes CVE-2024-7592.
\ No newline at end of file
diff --git a/tornado/__init__.py b/tornado/__init__.py
index f542de35..91e4cdec 100644
--- a/tornado/__init__.py
+++ b/tornado/__init__.py
@@ -22,8 +22,8 @@
 # is zero for an official release, positive for a development branch,
 # or negative for a release candidate or beta (after the base version
 # number has been incremented)
-version = "6.4.1"
-version_info = (6, 4, 0, 1)
+version = "6.4.2"
+version_info = (6, 4, 2, 0)
 
 import importlib
 import typing