diff --git a/typo3/sysext/fluid/Classes/Core/Rendering/RenderingContext.php b/typo3/sysext/fluid/Classes/Core/Rendering/RenderingContext.php
index 09a927eed0f3513772f7fd300ffc5b7d89405395..ca68d4353982461889b0fa2660011f96c92abfbb 100644
--- a/typo3/sysext/fluid/Classes/Core/Rendering/RenderingContext.php
+++ b/typo3/sysext/fluid/Classes/Core/Rendering/RenderingContext.php
@@ -238,9 +238,12 @@ class RenderingContext extends \TYPO3Fluid\Fluid\Core\Rendering\RenderingContext
      */
     public function setControllerAction($action)
     {
-        $action = lcfirst(pathinfo($action, PATHINFO_FILENAME));
+        $dotPosition = strpos($action, '.');
+        if ($dotPosition !== false) {
+            $action = substr($action, 0, $dotPosition);
+        }
         parent::setControllerAction($action);
-        $this->controllerContext->getRequest()->setControllerActionName($action);
+        $this->controllerContext->getRequest()->setControllerActionName(lcfirst($action));
     }
 
     /**
diff --git a/typo3/sysext/fluid/Tests/Unit/Core/Rendering/RenderingContextTest.php b/typo3/sysext/fluid/Tests/Unit/Core/Rendering/RenderingContextTest.php
index 005244d9dac19cfb57e4b263f7772ea41e26221c..afb6326d8dc98229fee6429b2c0a3aa535ee40f0 100644
--- a/typo3/sysext/fluid/Tests/Unit/Core/Rendering/RenderingContextTest.php
+++ b/typo3/sysext/fluid/Tests/Unit/Core/Rendering/RenderingContextTest.php
@@ -98,4 +98,38 @@ class RenderingContextTest extends \TYPO3\CMS\Components\TestingFramework\Core\U
         $this->renderingContext->_set('viewHelperVariableContainer', $viewHelperVariableContainer);
         $this->assertSame($viewHelperVariableContainer, $this->renderingContext->getViewHelperVariableContainer());
     }
+
+    /**
+     * @test
+     * @dataProvider getControllerActionTestValues
+     * @param string $input
+     * @param string $expected
+     */
+    public function setControllerActionProcessesInputCorrectly($input, $expected)
+    {
+        $subject = new RenderingContextFixture();
+        $request = $this->getMockBuilder(Request::class)->setMethods(['setControllerActionName'])->getMock();
+        $request->expects($this->at(0))->method('setControllerActionName')->with('index');
+        $request->expects($this->at(1))->method('setControllerActionName')->with(lcfirst($expected));
+        $controllerContext = $this->getMockBuilder(ControllerContext::class)->setMethods(['getRequest'])->getMock();
+        $controllerContext->expects($this->atLeastOnce())->method('getRequest')->willReturn($request);
+        $subject->setControllerContext($controllerContext);
+        $subject->setControllerAction($input);
+        $this->assertAttributeSame($expected, 'controllerAction', $subject);
+    }
+
+    /**
+     * @return array
+     */
+    public function getControllerActionTestValues()
+    {
+        return [
+            ['default', 'default'],
+            ['default.html', 'default'],
+            ['default.sub.html', 'default'],
+            ['Sub/Default', 'Sub/Default'],
+            ['Sub/Default.html', 'Sub/Default'],
+            ['Sub/Default.sub.html', 'Sub/Default']
+        ];
+    }
 }