diff --git a/publish/edit.php b/publish/edit.php
index b398574..c4f7cc5 100644
--- a/publish/edit.php
+++ b/publish/edit.php
@@ -64,7 +64,7 @@ Ordinary web users can:     write article
 
 $action = NULL;
 if (isset($_POST['action'])) {
-  $action = strtolower($_POST['action']);
+  $action = is_string($_POST['action']) ? strtolower($_POST['action']) : NULL;
 // We can trigger only choose and edit via GET variables.
 } else if (isset($_GET['action'])) {
   if ($_GET['action'] == 'choose') {
diff --git a/publish/index.php b/publish/index.php
index 06cb4f7..092bb8b 100644
--- a/publish/index.php
+++ b/publish/index.php
@@ -58,7 +58,7 @@ Ordinary web users can: 		write article
 */
 
 if (isset($_POST['action']))
-  $action = strtolower($_POST['action']);
+  $action = is_string($_POST['action']) ? strtolower($_POST['action']) : NULL;
 else
   $action = NULL;
 
diff --git a/publish/login.php b/publish/login.php
index 765e31d..529e4df 100644
--- a/publish/login.php
+++ b/publish/login.php
@@ -6,13 +6,14 @@ $denied = NULL;
 $wait_minutes = 0;
 $captcha_failed = FALSE;
 $is_admin = NULL;
+$login_name = is_string($_POST['username'] ?? NULL) ? $_POST['username'] : '';
 if (isset($_SESSION['editor'])) {
   session_write_close();
   header("Location: /publish/edit");
   return;
 } else if (isset($_POST['login']) && !csrf_valid()) {
   $denied = TRUE;
-} else if (isset($_POST['login']) && ($wait = login_blocked_for((string)($_POST['username'] ?? ''))) > 0) {
+} else if (isset($_POST['login']) && ($wait = login_blocked_for($login_name)) > 0) {
   $denied = TRUE;
   $wait_minutes = (int)ceil($wait / 60);
 } else if (isset($_POST['login']) && !captcha_verify_response()) {
@@ -23,7 +24,7 @@ if (isset($_SESSION['editor'])) {
   $table = "editors";
   open_db('open');
 
-  $username = (string)($_POST['username'] ?? '');
+  $username = $login_name;
   $query = "SELECT * FROM $table WHERE username = ? LIMIT 1";
   $getid = $db->execute_query($query, array($username)) or db_fail();
   $row = $getid->fetch_assoc();
diff --git a/tests/php/Pages/EditTest.php b/tests/php/Pages/EditTest.php
index eceb86c..9bfd7ae 100644
--- a/tests/php/Pages/EditTest.php
+++ b/tests/php/Pages/EditTest.php
@@ -72,6 +72,13 @@ class EditTest extends PageTestCase {
     $this->assertSame(array('5', 'Changed', 'Needs work'), array($row['id'], $row['title'], $row['comments']));
   }
 
+  public function testAnArrayActionIsIgnored(): void {
+    $this->loginAs();
+    $page = $this->post('/publish/edit', array('action' => array('delete'), 'id' => '1'));
+    $this->assertSame(200, $page['status']);
+    $this->assertSame(array(), $this->queries('/^(DELETE|INSERT|UPDATE)/'));
+  }
+
   public function testDeletingNeedsTheToken(): void {
     $page = $this->post('/publish/edit', array('action' => 'delete', 'id' => '1', 'queue' => '0', 'csrf_token' => 'wrong'));
     $this->assertStringContainsString('Your session has expired.', $page['body']);
diff --git a/tests/php/Pages/LoginTest.php b/tests/php/Pages/LoginTest.php
index 7ac7859..19065be 100644
--- a/tests/php/Pages/LoginTest.php
+++ b/tests/php/Pages/LoginTest.php
@@ -39,6 +39,14 @@ class LoginTest extends PageTestCase {
                           $this->get('/publish/login', array('X-Test-Plain' => '1', 'Host' => 'evil.example')));
   }
 
+  public function testAnArrayUsernameIsRefused(): void {
+    $token = $this->csrfToken($this->get('/publish/login')['body']);
+    $answer = $this->post('/publish/login', array('login' => '1', 'username' => array('ed'), 'password' => 'secret',
+                                                   'csrf_token' => $token, 'g-recaptcha-response' => 'pass'));
+    $this->assertSame(200, $answer['status']);
+    $this->assertStringContainsString('Access denied.', $answer['body']);
+  }
+
   public function testTheFormHasATokenAndTheCaptcha(): void {
     $body = $this->get('/publish/login')['body'];
     $this->assertSame($this->session()['csrf_token'], $this->csrfToken($body));
diff --git a/tests/php/Pages/SubmitTest.php b/tests/php/Pages/SubmitTest.php
index 7aeade2..77596b9 100644
--- a/tests/php/Pages/SubmitTest.php
+++ b/tests/php/Pages/SubmitTest.php
@@ -111,6 +111,13 @@ class SubmitTest extends PageTestCase {
     $this->assertSame(array(), $this->queries('/^INSERT/'));
   }
 
+  public function testAnArrayActionIsIgnored(): void {
+    $page = $this->post('/publish', array('action' => array('post')));
+    $this->assertSame(200, $page['status']);
+    $this->assertStringNotContainsString('Please review your submission.', $page['body']);
+    $this->assertSame(array(), $this->queries('/^INSERT/'));
+  }
+
   public function testFieldsAreEscapedInTheForm(): void {
     $token = $this->csrfToken($this->get('/publish')['body']);
     $page = $this->post('/publish', $this->story(array('action' => 'preview', 'csrf_token' => $token, 'g-recaptcha-response' => 'pass',