diff --git a/core/lib/Drupal/Core/Cache/DatabaseBackend.php b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
index 956662df40f..28da6cd7bf9 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseBackend.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
@@ -482,8 +482,11 @@ class DatabaseBackend implements CacheBackendInterface {
    */
   protected function normalizeCid($cid) {
     // Nothing to do if the ID is a US ASCII string of 255 characters or less.
+    // Additionally check for trailing spaces in the cache ID because MySQL
+    // may or may not take these into account when making comparisons.
+    // @see https://dev.mysql.com/doc/refman/9.0/en/char.html
     $cid_is_ascii = mb_check_encoding($cid, 'ASCII');
-    if (strlen($cid) <= 255 && $cid_is_ascii) {
+    if (strlen($cid) <= 255 && $cid_is_ascii && !str_ends_with($cid, ' ')) {
       return $cid;
     }
     // Return a string that uses as much as possible of the original cache ID
diff --git a/core/tests/Drupal/KernelTests/Core/Cache/GenericCacheBackendUnitTestBase.php b/core/tests/Drupal/KernelTests/Core/Cache/GenericCacheBackendUnitTestBase.php
index 4c970cf5b19..f30df8b054c 100644
--- a/core/tests/Drupal/KernelTests/Core/Cache/GenericCacheBackendUnitTestBase.php
+++ b/core/tests/Drupal/KernelTests/Core/Cache/GenericCacheBackendUnitTestBase.php
@@ -226,6 +226,13 @@ abstract class GenericCacheBackendUnitTestBase extends KernelTestBase {
     $this->assertEquals('value', $backend->get('TEST8')->data);
     $this->assertFalse($backend->get('test8'));
 
+    // Test a cid with and without a trailing space is treated as two different
+    // IDs.
+    $cid_nospace = 'trailing-space-test';
+    $backend->set($cid_nospace, $cid_nospace);
+    $this->assertSame($cid_nospace, $backend->get($cid_nospace)->data);
+    $this->assertFalse($backend->get($cid_nospace . ' '));
+
     // Calling ::set() with invalid cache tags. This should fail an assertion.
     try {
       $backend->set('assertion_test', 'value', Cache::PERMANENT, ['node' => [3, 5, 7]]);