diff --git a/Actions/ReadData.php b/Actions/ReadData.php
index 727f5fae6..e6e71968b 100644
--- a/Actions/ReadData.php
+++ b/Actions/ReadData.php
@@ -1,6 +1,8 @@
 <?php
 namespace exface\Core\Actions;
 
+use exface\Core\CommonLogic\ActionInputValidator;
+use exface\Core\Exceptions\Actions\ActionTaskInvalidException;
 use exface\Core\Interfaces\Actions\iReadData;
 use exface\Core\CommonLogic\AbstractAction;
 use exface\Core\Interfaces\DataSheets\DataSheetInterface;
@@ -43,6 +45,38 @@ class ReadData extends AbstractAction implements iReadData
     private ?UxonObject $customColumnsUxon = null;
     private ?UxonObject $customSortersUxon = null;
 
+    /**
+     * @inheritDoc
+     */
+    protected function validateApplicability(ActionInputValidator $validator): void
+    {
+        parent::validateApplicability($validator);
+
+        $expectedColumns = $validator->getExpectedColumns();
+        
+        try { 
+            $validator->validateTaskColumns($expectedColumns);
+        } catch (ActionTaskInvalidException $exception) {
+            $task = $validator->getTask();
+            if(!$task->hasInputData()) {
+                throw $exception;
+            }
+
+            // We ignore unexpected columns IF they are system columns.
+            $inputData = $task->getInputData();
+            foreach ($exception->getIssue(ActionTaskInvalidException::ISSUE_UNEXPECTED_COLUMN) as $badColumn) {
+                $col = $inputData->getColumns()->get($badColumn);
+                if(
+                    $col !== null &&
+                    $col->isAttribute() && 
+                    $col->getAttribute()->isSystem()
+                ) {
+                    $inputData->getColumns()->removeByKey($badColumn);
+                }
+            }
+        }
+    }
+
     /**
      * 
      * {@inheritDoc}
diff --git a/Actions/SaveData.php b/Actions/SaveData.php
index ae7ae67a7..37c1f72a2 100644
--- a/Actions/SaveData.php
+++ b/Actions/SaveData.php
@@ -1,6 +1,7 @@
 <?php
 namespace exface\Core\Actions;
 
+use exface\Core\CommonLogic\ActionInputValidator;
 use exface\Core\Interfaces\DataSheets\DataSheetInterface;
 use exface\Core\Interfaces\Actions\iModifyData;
 use exface\Core\Interfaces\Actions\iCanBeUndone;
@@ -41,6 +42,17 @@ protected function init()
         $this->setInputRowsMax(null);
     }
 
+    /**
+     * @inheritDoc
+     */
+    protected function validateApplicability(ActionInputValidator $validator): void
+    {
+        parent::validateApplicability($validator);
+        
+        $expectedColumns = $validator->getExpectedColumns();
+        $validator->validateTaskColumns($expectedColumns);
+    }
+
     /**
      * 
      * {@inheritDoc}
diff --git a/CommonLogic/AbstractAction.php b/CommonLogic/AbstractAction.php
index 2c012213d..58b8406be 100644
--- a/CommonLogic/AbstractAction.php
+++ b/CommonLogic/AbstractAction.php
@@ -4,6 +4,7 @@
 use exface\Core\CommonLogic\Actions\ActionConfirmationList;
 use exface\Core\CommonLogic\Traits\ICanBeConvertedToUxonTrait;
 use exface\Core\Exceptions\Actions\ActionConfigurationError;
+use exface\Core\Exceptions\Actions\ActionTaskInvalidException;
 use exface\Core\Interfaces\Actions\ActionConfirmationListInterface;
 use exface\Core\Interfaces\DataSheets\DataSheetInterface;
 use exface\Core\Interfaces\Log\LoggerInterface;
@@ -347,6 +348,9 @@ public final function handle(TaskInterface $task, DataTransactionInterface $tran
             $transaction = $this->getWorkbench()->data()->startTransaction();
         }
         
+        // TODO What's the correct response here? Throw, silent, message or something else.
+        $this->validateApplicability(new ActionInputValidator($this, $task));
+        
         $this->getWorkbench()->eventManager()->dispatch(new OnBeforeActionPerformedEvent($this, $task, $transaction, function() use ($task) {
             return $this->getInputDataSheet($task);
         }));
@@ -387,6 +391,20 @@ public final function handle(TaskInterface $task, DataTransactionInterface $tran
         return $result;
     }
 
+    /**
+     * Validates whether this action can be applied to a given task. Throws an error, when encountering issues
+     * and returns `void` if the task is valid for this action.
+     * 
+     * Base validation ensures that the task object and action object match, provided both are defined.
+     * 
+     * @throws ActionTaskInvalidException
+     * Throws an exception if validation FAILS, containing a description of the violation.
+     */
+    protected function validateApplicability(ActionInputValidator $validator) : void
+    {
+        $validator->validateTaskObject();
+    }
+    
     /**
      *
      * {@inheritdoc}
diff --git a/CommonLogic/ActionInputValidator.php b/CommonLogic/ActionInputValidator.php
new file mode 100644
index 000000000..880900ecb
--- /dev/null
+++ b/CommonLogic/ActionInputValidator.php
@@ -0,0 +1,249 @@
+<?php
+
+namespace exface\Core\CommonLogic;
+
+use exface\Core\Exceptions\Actions\ActionTaskInvalidException;
+use exface\Core\Interfaces\Actions\ActionInterface;
+use exface\Core\Interfaces\Tasks\TaskInterface;
+use exface\Core\Interfaces\WidgetInterface;
+use exface\Core\Interfaces\Widgets\iHaveColumns;
+use exface\Core\Interfaces\Widgets\iHaveConfigurator;
+use exface\Core\Interfaces\Widgets\iUseInputWidget;
+
+/**
+ * Wrapper class that contains various functions for validating action inputs. 
+ * 
+ * This class primarily exists to avoid unnecessary bloat in Actions, by limiting the availability of validation
+ * functions to any context where an instance of this class is present.
+ */
+class ActionInputValidator
+{
+    protected ActionInterface $action;
+    protected TaskInterface $task;
+
+    /**
+     * Creates a new instance and binds it to the given action and task. 
+     * 
+     * NOTE: Neither of these references can be changed. Create a new instance if you want to validate a different 
+     * combination of task and action.
+     * 
+     * @param ActionInterface $action
+     * @param TaskInterface   $task
+     */
+    function __construct(ActionInterface $action, TaskInterface $task)
+    {
+        $this->action = $action;
+        $this->task = $task;
+    }
+
+    /**
+     * Validates the task object and throws an error, should validation fail.
+     * 
+     * NOTE: If either the task or the action do not have an object, validation succeeds.
+     * 
+     * @return void
+     * @throws ActionTaskInvalidException
+     */
+    public function validateTaskObject() : void
+    {
+        $action = $this->getAction();
+        $task = $this->getTask();
+        
+        $taskObject = $task->hasMetaObject() ? $task->getMetaObject() : null;
+        $actionObject = $action->hasMetaObject() ? $action->getMetaObject() : null;
+
+        if($taskObject === null || $actionObject === null) {
+            return;
+        }
+
+        // Ensure metaobjects match.
+        if(!$taskObject->isExactly($actionObject)) {
+
+            // See if any input mapper has a matching from object.
+            // If we can't match with an input mapper either, the task is invalid for this action.
+            if(!$action->getInputMapper($taskObject) !== null) {
+                $taskAlias = $taskObject->getAliasWithNamespace();
+                
+                $error = new ActionTaskInvalidException(
+                    $action,
+                    $task,
+                    'Action "' . $action->getAliasWithNamespace() . '" is defined for "' .
+                    $actionObject->getAliasWithNamespace() . '", but received a task with object "' .
+                    $taskAlias . '"!'
+                );
+                
+                $error->setUseExceptionMessageAsTitle(true);
+                $error->addIssue(ActionTaskInvalidException::ISSUE_INVALID_OBJECT, $taskAlias);
+                
+                throw $error;
+            }
+        }
+    }
+
+    /**
+     * Returns an array containing the names of columns that the action expects in its input data.
+     * To explicitly allow certain columns, simply add them to the array.
+     *
+     * @param string               $widgetPrepareDataSheetFunction
+     * You can specify what getter you wish to use, to retrieve a datasheet from the input widget. Make sure the 
+     * function is actually supported by the input widget and returns an instance of `DataSheetInterface`.
+     * @param WidgetInterface|null $inputWidget
+     * Specify an input widget. If ´null´, the input widget will be determined automatically.
+     * @return array
+     */
+    public function getExpectedColumns(
+        string $widgetPrepareDataSheetFunction = 'prepareDataSheetToRead',
+        WidgetInterface $inputWidget = null
+    ) : array
+    {
+        $expectedColumns = [];
+        
+        $inputWidget = $inputWidget ?? $this->getInputWidget();
+        if($inputWidget === null) {
+            return $expectedColumns;
+        }
+        
+        $this->addColumnsFromWidget(
+            $expectedColumns,
+            $inputWidget,
+            $widgetPrepareDataSheetFunction
+        );
+
+        if($inputWidget instanceof iHaveConfigurator) {
+            $this->addColumnsFromWidget(
+                $expectedColumns,
+                $inputWidget->getConfiguratorWidget(),
+                'prepareDataSheetToRead'
+            );
+        }
+        
+        if($inputWidget instanceof iHaveColumns) {
+            foreach ($inputWidget->getColumns() as $column) {
+                $name = $column->getDataColumnName();
+                $expectedColumns[$name] = $name;
+            }
+        }
+        
+        return $expectedColumns;
+    }
+
+    /**
+     * Deduces the input widget for the action.
+     * 
+     * @return WidgetInterface|null
+     */
+    protected function getInputWidget() : WidgetInterface|null
+    {
+        $task = $this->getTask();
+        $action = $this->getAction();
+        
+        if($task->isTriggeredByWidget()) {
+            $widget = $task->getWidgetTriggeredBy();
+        } elseif ($action->isDefinedInWidget()) {
+            $widget = $action->getWidgetDefinedIn();
+        } else {
+            return null;
+        }
+
+        if($widget instanceof iUseInputWidget) {
+            $widget = $widget->getInputWidget();
+        }
+
+        return $widget;
+    }
+
+    /**
+     * Adds all columns from a given widget to 
+     * 
+     * @param array           $target
+     * @param WidgetInterface $widget
+     * @param string          $widgetPrepareDataSheetFunction
+     * @return void
+     */
+    protected function addColumnsFromWidget(
+        array &$target,
+        WidgetInterface $widget,
+        string $widgetPrepareDataSheetFunction
+    ) : void
+    {
+        try {
+            foreach ($widget->$widgetPrepareDataSheetFunction()->getColumns() as $column) {
+                $name = $column->getName();
+                $target[$name] = $name;
+            }
+        } catch (\Throwable $exception) {
+
+        }
+    }
+
+    /**
+     * Validates the task against a given list of columns. If any column in the task's input data is NOT among the
+     * `$expectedColumns` an error will be thrown.
+     * 
+     * Validation succeeds if all input columns are expected or if the task doesn't have input data.
+     * 
+     * @param array $expectedColumns
+     * @return void
+     */
+    public function validateTaskColumns(
+        array $expectedColumns
+    ) : void
+    {
+        if(empty($expectedColumns)) {
+            return;
+        }
+
+        $action = $this->getAction();
+        $task = $this->getTask();
+        
+        // See if the task has input data.
+        if(!$task->hasInputData()) {
+            return;
+        }
+
+        $taskInput = $task->getInputData();
+        $unexpectedColumns = [];
+
+        // Now check if there are input columns that are not present in our expected structure, which would imply
+        // a mistake or unauthorized attempts at accessing or manipulating data. Note that missing input columns
+        // are of no concern here, since they might be handled later by mappers or prototype specific logic.
+        foreach ($taskInput->getColumns() as $inputColumn) {
+            $inputColumnName = $inputColumn->getName();
+            if(!key_exists($inputColumnName, $expectedColumns)) {
+                $unexpectedColumns[$inputColumnName] = '"' . $inputColumnName . '"';
+            }
+        }
+
+        if(!empty($unexpectedColumns)) {
+            $error = new ActionTaskInvalidException(
+                $action,
+                $task,
+                'Unexpected task input columns detected for action "' . $action->getAliasWithNamespace() .
+                '": ' . implode(', ', $unexpectedColumns) . '!'
+            );
+            
+            $error->setUseExceptionMessageAsTitle(true);
+            foreach (array_keys($unexpectedColumns) as $unexpectedColumn) {
+                $error->addIssue(ActionTaskInvalidException::ISSUE_UNEXPECTED_COLUMN, $unexpectedColumn);
+            }
+            
+            throw $error;
+        }
+    }
+
+    /**
+     * @return ActionInterface
+     */
+    public function getAction() : ActionInterface
+    {
+        return $this->action;
+    }
+
+    /**
+     * @return TaskInterface
+     */
+    public function getTask() : TaskInterface
+    {
+        return $this->task;
+    }
+}
\ No newline at end of file
diff --git a/Exceptions/Actions/ActionTaskInvalidException.php b/Exceptions/Actions/ActionTaskInvalidException.php
new file mode 100644
index 000000000..6d41e07e8
--- /dev/null
+++ b/Exceptions/Actions/ActionTaskInvalidException.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace exface\Core\Exceptions\Actions;
+
+use exface\Core\Interfaces\Actions\ActionInterface;
+use exface\Core\Interfaces\Tasks\TaskInterface;
+
+class ActionTaskInvalidException extends ActionInputError
+{
+    public const ISSUE_INVALID_OBJECT = 'invalidObject';
+    public const ISSUE_UNEXPECTED_COLUMN = 'unexpectedColumn';
+    
+    private TaskInterface $task;
+    private array $issues = [];
+    
+    public function __construct(ActionInterface $action, TaskInterface $task, $message, $alias = null, $previous = null)
+    {
+        $this->task = $task;
+        parent::__construct($action, $message, $alias, $previous);
+    }
+
+    public function getTask() : TaskInterface
+    {
+        return $this->task;
+    }
+    
+    public function addIssue(string $issue, string $alias) : void
+    {
+        $this->issues[$issue][$alias] = $alias;
+    }
+    
+    public function getIssuesAll() : array
+    {
+        return $this->issues;
+    }
+    
+    public function getIssue(string $issue) : array
+    {
+        return $this->issues[$issue] ?? [];
+    }
+}
\ No newline at end of file