diff --git a/CHANGELOG.md b/CHANGELOG.md
index 62320ab46951..ebe0ba8c08a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@
   - Moved to Stage 3, [March TC39 meeting](https://github.com/babel/proposals/issues/81#issuecomment-1083449843)
   - `Array.prototype.toSpliced` throws a `TypeError` instead of `RangeError` if the result length is more than `MAX_SAFE_INTEGER`, [proposal-change-array-by-copy/70](https://github.com/tc39/proposal-change-array-by-copy/pull/70)
 - Added some more `atob` / `btoa` fixes:
+  - NodeJS <17.9 `atob` does not ignore spaces, [node/42530](https://github.com/nodejs/node/issues/42530)
+  - Actual NodeJS `atob` does not validate encoding, [node/42646](https://github.com/nodejs/node/issues/42646)
   - FF26- implementation does not properly convert argument to string
   - IE / Edge <16 implementation have wrong arity
 - Significant internal refactoring and splitting of modules (but without exposing to public API since it will be a breaking change - it will be exposed in the next major version)
@@ -13,7 +15,6 @@
 - Tooling:
   - Stabilized proposals are filtered out from the `core-js-compat` -> `core-js-builder` -> `core-js-bundle` output. That mean that if the output contains, for example, `es.object.has-own`, the legacy reference to it, `esnext.object.has-own`, will not be added.
 - Compat data:
-  - `atob` marked as not supported in the actual NodeJS (again) because of [the bug](https://github.com/nodejs/node/issues/42530)
   - `.stack` property on `DOMException` marked as supported from Deno [1.15](https://github.com/denoland/deno/releases/tag/v1.15.0)
   - Added Deno 1.21 compat data mapping
   - Added Electron 19.0 and updated 18.0 compat data mapping
diff --git a/packages/core-js-compat/src/data.mjs b/packages/core-js-compat/src/data.mjs
index 7121bf6b8638..858b0b4b4cce 100644
--- a/packages/core-js-compat/src/data.mjs
+++ b/packages/core-js-compat/src/data.mjs
@@ -1915,7 +1915,8 @@ export const data = {
     firefox: '27',
     // https://github.com/nodejs/node/issues/41450
     // https://github.com/nodejs/node/issues/42530
-    // node: '17.5', '16.0',
+    // https://github.com/nodejs/node/issues/42646
+    // node: '17.9', 17.5', '16.0',
     opera: '10.5',
     safari: '10.1',
   },
diff --git a/packages/core-js/modules/web.atob.js b/packages/core-js/modules/web.atob.js
index 3e0761b1b5d3..d9674712c2b9 100644
--- a/packages/core-js/modules/web.atob.js
+++ b/packages/core-js/modules/web.atob.js
@@ -18,18 +18,22 @@ var replace = uncurryThis(''.replace);
 var exec = uncurryThis(disallowed.exec);
 
 var NO_SPACES_IGNORE = fails(function () {
-  return atob(' ') !== '';
+  return $atob(' ') !== '';
 });
 
-var NO_ARG_RECEIVING_CHECK = !NO_SPACES_IGNORE && !fails(function () {
+var NO_ENCODING_CHECK = !fails(function () {
+  $atob('a');
+});
+
+var NO_ARG_RECEIVING_CHECK = !NO_SPACES_IGNORE && !NO_ENCODING_CHECK && !fails(function () {
   $atob();
 });
 
-var WRONG_ARITY = !NO_SPACES_IGNORE && $atob.length !== 1;
+var WRONG_ARITY = !NO_SPACES_IGNORE && !NO_ENCODING_CHECK && $atob.length !== 1;
 
 // `atob` method
 // https://html.spec.whatwg.org/multipage/webappapis.html#dom-atob
-$({ global: true, enumerable: true, forced: NO_SPACES_IGNORE || NO_ARG_RECEIVING_CHECK || WRONG_ARITY }, {
+$({ global: true, enumerable: true, forced: NO_SPACES_IGNORE || NO_ENCODING_CHECK || NO_ARG_RECEIVING_CHECK || WRONG_ARITY }, {
   atob: function atob(data) {
     validateArgumentsLength(arguments.length, 1);
     if (NO_ARG_RECEIVING_CHECK || WRONG_ARITY) return $atob(data);
diff --git a/tests/compat/tests.js b/tests/compat/tests.js
index f5990501f60e..3c3978d1fbed 100644
--- a/tests/compat/tests.js
+++ b/tests/compat/tests.js
@@ -1696,8 +1696,12 @@ GLOBAL.tests = {
   'web.atob': function () {
     try {
       atob();
-    } catch (error) {
-      return atob(' ') === '';
+    } catch (error1) {
+      try {
+        atob('a');
+      } catch (error2) {
+        return atob(' ') === '';
+      }
     }
   },
   'web.btoa': function () {