diff --git a/AUTHORS b/AUTHORS
index c800afe9d5..ab566080de 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -290,6 +290,7 @@ Filip Stollár
 Filype Pereira
 finalfantasia
 flack
+flofriday
 Florian Felten
 Fons van der Plas
 Forbes Lindesay
@@ -356,6 +357,7 @@ Hendrik Erz
 Hendrik Wallbaum
 Henrik Haugbølle
 Herculano Campos
+Hicham Omari
 hidaiy
 Hiroyuki Makino
 hitsthings
@@ -466,6 +468,7 @@ Joo
 Joost-Wim Boekesteijn
 José dBruxelles
 Joseph D. Purcell
+Joseph Olstad
 Joseph Pecoraro
 Josh Barnes
 Josh Cohen
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8a7064be6a..02544da534 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+## 5.65.21 (2026-02-07)
+
+### Bug fixes
+
+Better handle configuration objects with a null prototype.
+
+[kotlin mode](https://codemirror.net/5/mode/clike/): Fix tokenizing of unsigned long literals.
+
 ## 5.65.20 (2025-08-10)
 
 ### Bug fixes
diff --git a/doc/manual.html b/doc/manual.html
index 3ea659e970..84fe6e965c 100644
--- a/doc/manual.html
+++ b/doc/manual.html
@@ -70,7 +70,7 @@
 <section class=first id=overview>
     <h2 style="position: relative">
       User manual and reference guide
-      <span style="color: #888; font-size: 1rem; position: absolute; right: 0; bottom: 0">version 5.65.20</span>
+      <span style="color: #888; font-size: 1rem; position: absolute; right: 0; bottom: 0">version 5.65.21</span>
     </h2>
 
     <p>CodeMirror is a code-editor component that can be embedded in
diff --git a/doc/releases.html b/doc/releases.html
index 42227c7316..422232edff 100644
--- a/doc/releases.html
+++ b/doc/releases.html
@@ -34,7 +34,12 @@ <h2>Version 6.x</h2>
 
   <h2>Version 5.x</h2>
 
-  <p class="rel">10-08-2025: <a href="https://codemirror.net/5/codemirror-5.65.20.zip">Version 5.65.20</a>:</p>
+  <p class="rel">07-02-2026: <a href="https://codemirror.net/5/codemirror-5.65.21.zip">Version 5.65.21</a>:</p>
+
+  <ul class="rel-note">
+    <li>Better handle configuration objects with a null prototype.
+    <li><a href="https://codemirror.net/5/mode/clike/">kotlin mode</a>: Fix tokenizing of unsigned long literals.
+  </ul>
 
   <ul class="rel-note">
     <li><a href="https://codemirror.net/5/doc/manual.html#addon_show-hint">show-hint addon</a>: Fix a positioning issue when the tooltip is at the bottom of the screen.
diff --git a/index.html b/index.html
index 7cc603ccbc..d8c1e983bb 100644
--- a/index.html
+++ b/index.html
@@ -92,7 +92,7 @@ <h2>This is CodeMirror</h2>
   </script>
 
   <div class=actions>
-    Get the current version: <a href="https://codemirror.net/5/codemirror.zip">5.65.20</a>.<br>
+    Get the current version: <a href="https://codemirror.net/5/codemirror.zip">5.65.21</a>.<br>
     You can see the <a href="https://github.com/codemirror/codemirror5" title="GitHub repository">code</a>,<br>
     read the <a href="doc/releases.html">release notes</a>,<br>
     or study the <a href="doc/manual.html">user manual</a>.
diff --git a/package.json b/package.json
index 330bfeb30a..76a5175be7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "codemirror",
-  "version": "5.65.20",
+  "version": "5.65.21",
   "main": "lib/codemirror.js",
   "style": "lib/codemirror.css",
   "author": {
diff --git a/src/edit/main.js b/src/edit/main.js
index 949d9d4031..610a205c3e 100644
--- a/src/edit/main.js
+++ b/src/edit/main.js
@@ -66,4 +66,4 @@ import { addLegacyProps } from "./legacy.js"
 
 addLegacyProps(CodeMirror)
 
-CodeMirror.version = "5.65.20"
+CodeMirror.version = "5.65.21"