diff --git a/CHANGELOG.md b/CHANGELOG.md
index efa525eb1aa..7bf9ce4eef3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
 - Fixed a bug where `craft\helpers\DateTimeHelper::toDateInterval()` didn’t support negative integers. ([#13463](https://github.com/craftcms/cms/pull/13463))
 - Fixed a bug where admin tables were initially displaying an empty results message rather than a loading spinner, when the initial data was loading via Ajax. ([#13459](https://github.com/craftcms/cms/issues/13459))
 - Fixed a bug where garbage collection could terminate prematurely if an exception was thrown when deleting a pending user. ([#13490](https://github.com/craftcms/cms/issues/13490))
+- Fixed an error that occurred if the `purify` Twig filter was applied to a `null` value. ([#13495](https://github.com/craftcms/cms/issues/13495))
 - Fixed an information disclosure vulnerability.
 
 ## 4.4.16.1 - 2023-07-19
diff --git a/src/web/twig/Extension.php b/src/web/twig/Extension.php
index e55bafdf6ff..19d1953e8eb 100644
--- a/src/web/twig/Extension.php
+++ b/src/web/twig/Extension.php
@@ -801,14 +801,18 @@ public function prependFilter(string $tag, string $html, ?string $ifExists = nul
     /**
      * Purifies the given HTML using HTML Purifier.
      *
-     * @param string $html The HTML to be purified
+     * @param string|null $html The HTML to be purified
      * @param string|array|null $config The HTML Purifier config. This can either be the name of a JSON file within
      * `config/htmlpurifier/` (sans `.json` extension) or a config array.
-     * @return string The purified HTML
+     * @return string|null The purified HTML
      * @since 3.4.0
      */
-    public function purifyFilter(string $html, array|string|null $config = null): string
+    public function purifyFilter(?string $html, array|string|null $config = null): ?string
     {
+        if ($html === null) {
+            return null;
+        }
+
         if (is_string($config)) {
             $path = Craft::$app->getPath()->getConfigPath() . DIRECTORY_SEPARATOR . 'htmlpurifier' .
                 DIRECTORY_SEPARATOR . $config . '.json';