diff --git a/CHANGELOG.md b/CHANGELOG.md
index 770c85f..3971419 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Add Transifex translations link to README
 
+### Fixed
+
+- Fix `Clear` checkbox not erasing the stored SCCM database password and inventory credentials
+
 ## [2.7.0] - 2026-10-06
 
 ### Added
diff --git a/inc/config.class.php b/inc/config.class.php
index 6622c5f..9d2dda2 100644
--- a/inc/config.class.php
+++ b/inc/config.class.php
@@ -142,16 +142,15 @@ public function prepareInputForAdd($input): array
 
     public function prepareInputForUpdate($input): array
     {
-        if (isset($input["sccmdb_password"]) && !empty($input["sccmdb_password"])) {
-            $input["sccmdb_password"] = (new GLPIKey())->encrypt($input["sccmdb_password"]);
-        } else {
-            unset($input["sccmdb_password"]);
-        }
-
-        if (isset($input["auth_info"]) && !empty($input["auth_info"])) {
-            $input["auth_info"] = (new GLPIKey())->encrypt($input["auth_info"]);
-        } else {
-            unset($input["auth_info"]);
+        foreach (['sccmdb_password', 'auth_info'] as $field) {
+            // "Clear" checkbox rendered by GLPI password fields
+            if (!empty($input['_blank_' . $field])) {
+                $input[$field] = '';
+            } elseif (!empty($input[$field])) {
+                $input[$field] = (new GLPIKey())->encrypt($input[$field]);
+            } else {
+                unset($input[$field]);
+            }
         }
 
         if (array_key_exists('inventory_server_url', $input) && !empty($input['inventory_server_url'])) {
diff --git a/tests/PluginSccmConfigTest.php b/tests/PluginSccmConfigTest.php
new file mode 100644
index 0000000..e531b1b
--- /dev/null
+++ b/tests/PluginSccmConfigTest.php
@@ -0,0 +1,79 @@
+<?php
+
+/**
+ * -------------------------------------------------------------------------
+ * SCCM plugin for GLPI
+ * -------------------------------------------------------------------------
+ *
+ * LICENSE
+ *
+ * This file is part of SCCM.
+ *
+ * SCCM is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * SCCM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with SCCM. If not, see <http://www.gnu.org/licenses/>.
+ * -------------------------------------------------------------------------
+ * @author    François Legastelois
+ * @copyright Copyright (C) 2014-2023 by SCCM plugin team.
+ * @license   GPLv3 https://www.gnu.org/licenses/gpl-3.0.html
+ * @link      https://github.com/pluginsGLPI/sccm
+ * -------------------------------------------------------------------------
+ */
+
+use Glpi\Tests\DbTestCase;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+class PluginSccmConfigTest extends DbTestCase
+{
+    public static function secretFieldProvider(): iterable
+    {
+        yield 'database password' => ['sccmdb_password'];
+        yield 'inventory credentials' => ['auth_info'];
+    }
+
+    #[DataProvider('secretFieldProvider')]
+    public function testSecretIsEncrypted(string $field): void
+    {
+        $config = $this->createItem(PluginSccmConfig::class, ['name' => 'test', $field => 'secret'], [$field]);
+
+        $this->assertNotSame('secret', $config->fields[$field]);
+        $this->assertSame('secret', (new GLPIKey())->decrypt($config->fields[$field]));
+    }
+
+    #[DataProvider('secretFieldProvider')]
+    public function testEmptySecretKeepsStoredValue(string $field): void
+    {
+        $config = $this->createItem(PluginSccmConfig::class, ['name' => 'test', $field => 'secret'], [$field]);
+
+        $this->updateItem(PluginSccmConfig::class, $config->getID(), [$field => ''], [$field]);
+
+        $this->assertTrue($config->getFromDB($config->getID()));
+        $this->assertSame('secret', (new GLPIKey())->decrypt($config->fields[$field]));
+    }
+
+    #[DataProvider('secretFieldProvider')]
+    public function testClearCheckboxErasesSecret(string $field): void
+    {
+        $config = $this->createItem(PluginSccmConfig::class, ['name' => 'test', $field => 'secret'], [$field]);
+
+        // The form still posts the displayed value along with the checkbox
+        $this->updateItem(
+            PluginSccmConfig::class,
+            $config->getID(),
+            [$field => 'secret', '_blank_' . $field => '1'],
+            [$field, '_blank_' . $field],
+        );
+
+        $this->assertTrue($config->getFromDB($config->getID()));
+        $this->assertEmpty($config->fields[$field]);
+    }
+}