diff --git a/tests/system/Config/BaseConfigTest.php b/tests/system/Config/BaseConfigTest.php
index 0ba70346de4c..9158db34140f 100644
--- a/tests/system/Config/BaseConfigTest.php
+++ b/tests/system/Config/BaseConfigTest.php
@@ -197,6 +197,9 @@ public function testSetsDefaultValues(): void
     #[RunInSeparateProcess]
     public function testSetsDefaultValuesEncryptionUsingHex2Bin(): void
     {
+        putenv('encryption.key');
+        unset($_ENV['encryption.key'], $_SERVER['encryption.key']); // @phpstan-ignore codeigniter.superglobalAccess
+
         $dotenv = new DotEnv($this->fixturesFolder, 'encryption.env');
         $dotenv->load();
         $config = new Encryption();
@@ -210,6 +213,9 @@ public function testSetsDefaultValuesEncryptionUsingHex2Bin(): void
     #[RunInSeparateProcess]
     public function testSetDefaultValuesEncryptionUsingBase64(): void
     {
+        putenv('encryption.key');
+        unset($_ENV['encryption.key'], $_SERVER['encryption.key']); // @phpstan-ignore codeigniter.superglobalAccess
+
         $dotenv = new DotEnv($this->fixturesFolder, 'base64encryption.env');
         $dotenv->load();
         $config = new Encryption('base64');
diff --git a/tests/system/Config/DotEnvTest.php b/tests/system/Config/DotEnvTest.php
index 6fd287be6ad5..97bf2e3dd026 100644
--- a/tests/system/Config/DotEnvTest.php
+++ b/tests/system/Config/DotEnvTest.php
@@ -90,6 +90,9 @@ public static function provideLoadsVars(): iterable
     #[RunInSeparateProcess]
     public function testLoadsHex2Bin(): void
     {
+        putenv('encryption.key');
+        unset($_ENV['encryption.key'], $_SERVER['encryption.key']); // @phpstan-ignore codeigniter.superglobalAccess
+
         $dotenv = new DotEnv($this->fixturesFolder, 'encryption.env');
         $dotenv->load();
 
@@ -102,6 +105,9 @@ public function testLoadsHex2Bin(): void
     #[RunInSeparateProcess]
     public function testLoadsBase64(): void
     {
+        putenv('encryption.key');
+        unset($_ENV['encryption.key'], $_SERVER['encryption.key']); // @phpstan-ignore codeigniter.superglobalAccess
+
         $dotenv = new DotEnv($this->fixturesFolder, 'base64encryption.env');
         $dotenv->load();