diff --git a/_data/origin/cors.yml b/_data/origin/cors.yml
index 5be89c1..b6c8674 100644
--- a/_data/origin/cors.yml
+++ b/_data/origin/cors.yml
@@ -8,8 +8,8 @@ cdns:
   - url: https://fonts.googleapis.com
   # jsDelivr CDN
   - url: https://cdn.jsdelivr.net
-  # polyfill.io for math
-  - url: https://polyfill.io
+  # polyfill.io for math (cdnjs.cloudflare.com/polyfill)
+  - url: https://cdnjs.cloudflare.com
 
 # fonts
 
diff --git a/_includes/js-selector.html b/_includes/js-selector.html
index 65c6453..662e9a4 100644
--- a/_includes/js-selector.html
+++ b/_includes/js-selector.html
@@ -91,7 +91,7 @@
       }
     };
   </script>
-  <script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
+  <script src="https://cdnjs.cloudflare.com/polyfill/v3/polyfill.min.js?features=es6"></script>
   <script id="MathJax-script" async src="{{ site.data.origin[type].mathjax.js | relative_url }}"></script>
 {% endif %}
 
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 73c7421..6db73fe 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 All notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.
 
+## [6.5.3](https://github.com/cotes2020/jekyll-theme-chirpy/compare/v6.5.2...v6.5.3) (2024-03-07)
+
 ## [6.5.2](https://github.com/cotes2020/jekyll-theme-chirpy/compare/v6.5.1...v6.5.2) (2024-02-29)
 
 ### Bug Fixes
diff --git a/jekyll-theme-chirpy.gemspec b/jekyll-theme-chirpy.gemspec
index 714b24f..3287993 100644
--- a/jekyll-theme-chirpy.gemspec
+++ b/jekyll-theme-chirpy.gemspec
@@ -2,7 +2,7 @@
 
 Gem::Specification.new do |spec|
   spec.name          = "jekyll-theme-chirpy"
-  spec.version       = "6.5.2"
+  spec.version       = "6.5.3"
   spec.authors       = ["Cotes Chung"]
   spec.email         = ["cotes.chung@gmail.com"]
 
diff --git a/package.json b/package.json
index 72d9128..5dd42b3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "jekyll-theme-chirpy",
-  "version": "6.5.2",
+  "version": "6.5.3",
   "description": "A minimal, responsive, and feature-rich Jekyll theme for technical writing.",
   "repository": {
     "type": "git",