diff --git a/vendor/magento/module-security/Model/AdminSessionInfo.php b/vendor/magento/module-security/Model/AdminSessionInfo.php
index c14d399e98c..b0347fdbc3a 100644
--- a/vendor/magento/module-security/Model/AdminSessionInfo.php
+++ b/vendor/magento/module-security/Model/AdminSessionInfo.php
@@ -47,6 +47,7 @@ class AdminSessionInfo extends \Magento\Framework\Model\AbstractModel
     /**
      * All other open sessions were terminated
      * @since 100.1.0
+     * @var bool
      */
     protected $isOtherSessionsTerminated = false;
 
@@ -133,10 +134,10 @@ class AdminSessionInfo extends \Magento\Framework\Model\AbstractModel
         $currentTime = $this->dateTime->gmtTimestamp();
         $lastUpdatedTime = $this->getUpdatedAt();
         if (!is_numeric($lastUpdatedTime)) {
-            $lastUpdatedTime = strtotime($lastUpdatedTime);
+            $lastUpdatedTime = $lastUpdatedTime === null ? 0 : strtotime($lastUpdatedTime);
         }
 
-        return $lastUpdatedTime <= ($currentTime - $lifetime) ? true : false;
+        return $lastUpdatedTime <= ($currentTime - $lifetime);
     }
 
     /**
diff --git a/vendor/magento/module-security/Model/AdminSessionsManager.php b/vendor/magento/module-security/Model/AdminSessionsManager.php
index 154760eb835..e6b7a076e1c 100644
--- a/vendor/magento/module-security/Model/AdminSessionsManager.php
+++ b/vendor/magento/module-security/Model/AdminSessionsManager.php
@@ -7,7 +7,10 @@ declare(strict_types=1);
 
 namespace Magento\Security\Model;
 
+use Magento\Backend\Model\Auth\Session;
 use Magento\Framework\HTTP\PhpEnvironment\RemoteAddress;
+use Magento\Framework\Stdlib\DateTime;
+use Magento\Security\Model\ResourceModel\AdminSessionInfo\Collection;
 use Magento\Security\Model\ResourceModel\AdminSessionInfo\CollectionFactory;
 
 /**
@@ -15,6 +18,7 @@ use Magento\Security\Model\ResourceModel\AdminSessionInfo\CollectionFactory;
  *
  * @api
  * @since 100.1.0
+ * @SuppressWarnings(PHPMD.CookieAndSessionMisuse)
  */
 class AdminSessionsManager
 {
@@ -35,7 +39,7 @@ class AdminSessionsManager
     protected $securityConfig;
 
     /**
-     * @var \Magento\Backend\Model\Auth\Session
+     * @var Session
      * @since 100.1.0
      */
     protected $authSession;
@@ -73,12 +77,14 @@ class AdminSessionsManager
      *
      * Means that after session was prolonged
      * all other prolongs will be ignored within this period
+     *
+     * @var int
      */
     private $maxIntervalBetweenConsecutiveProlongs = 60;
 
     /**
      * @param ConfigInterface $securityConfig
-     * @param \Magento\Backend\Model\Auth\Session $authSession
+     * @param Session $authSession
      * @param AdminSessionInfoFactory $adminSessionInfoFactory
      * @param CollectionFactory $adminSessionInfoCollectionFactory
      * @param \Magento\Framework\Stdlib\DateTime\DateTime $dateTime
@@ -86,7 +92,7 @@ class AdminSessionsManager
      */
     public function __construct(
         ConfigInterface $securityConfig,
-        \Magento\Backend\Model\Auth\Session $authSession,
+        Session $authSession,
         \Magento\Security\Model\AdminSessionInfoFactory $adminSessionInfoFactory,
         \Magento\Security\Model\ResourceModel\AdminSessionInfo\CollectionFactory $adminSessionInfoCollectionFactory,
         \Magento\Framework\Stdlib\DateTime\DateTime $dateTime,
@@ -138,7 +144,7 @@ class AdminSessionsManager
             $this->getCurrentSession()->setData(
                 'updated_at',
                 date(
-                    \Magento\Framework\Stdlib\DateTime::DATETIME_PHP_FORMAT,
+                    DateTime::DATETIME_PHP_FORMAT,
                     $this->authSession->getUpdatedAt()
                 )
             );
@@ -204,7 +210,7 @@ class AdminSessionsManager
             case AdminSessionInfo::LOGGED_OUT_BY_LOGIN:
                 $reasonMessage = __(
                     'Someone logged into this account from another device or browser.'
-                    .' Your current session is terminated.'
+                    . ' Your current session is terminated.'
                 );
                 break;
             case AdminSessionInfo::LOGGED_OUT_MANUALLY:
@@ -241,7 +247,7 @@ class AdminSessionsManager
     /**
      * Get sessions for current user
      *
-     * @return \Magento\Security\Model\ResourceModel\AdminSessionInfo\Collection
+     * @return Collection
      * @since 100.1.0
      */
     public function getSessionsForCurrentUser()
@@ -314,7 +320,9 @@ class AdminSessionsManager
     }
 
     /**
-     * @return \Magento\Security\Model\ResourceModel\AdminSessionInfo\Collection
+     * Retrieve new instance of admin session info collection
+     *
+     * @return Collection
      * @since 100.1.0
      */
     protected function createAdminSessionInfoCollection()
@@ -323,24 +331,27 @@ class AdminSessionsManager
     }
 
     /**
-     * Calculates diff between now and last session updated_at
-     * and decides whether new prolong must be triggered or not
+     * Calculates diff between now and last session updated_at and decides whether new prolong must be triggered or not
      *
      * This is done to limit amount of session prolongs and updates to database
      * within some period of time - X
      * X - is calculated in getIntervalBetweenConsecutiveProlongs()
      *
-     * @see getIntervalBetweenConsecutiveProlongs()
      * @return bool
+     * @see getIntervalBetweenConsecutiveProlongs()
      */
     private function lastProlongIsOldEnough()
     {
-        $lastProlongTimestamp = strtotime($this->getCurrentSession()->getUpdatedAt());
+        $lastUpdatedTime = $this->getCurrentSession()->getUpdatedAt();
+        if ($lastUpdatedTime === null || is_numeric($lastUpdatedTime)) {
+            $lastUpdatedTime = "now";
+        }
+        $lastProlongTimestamp = strtotime($lastUpdatedTime);
         $nowTimestamp = $this->authSession->getUpdatedAt();
 
         $diff = $nowTimestamp - $lastProlongTimestamp;
 
-        return (float) $diff > $this->getIntervalBetweenConsecutiveProlongs();
+        return (float)$diff > $this->getIntervalBetweenConsecutiveProlongs();
     }
 
     /**
@@ -354,7 +365,7 @@ class AdminSessionsManager
      */
     private function getIntervalBetweenConsecutiveProlongs()
     {
-        return (float) max(
+        return (float)max(
             1,
             min(
                 4 * log((float)$this->securityConfig->getAdminSessionLifetime()),