diff --git a/CHANGELOG b/CHANGELOG
index f2334eb51..50512f0b0 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -35,6 +35,7 @@ CHANGELOG Roundcube Webmail
 - Fix bug where message content could overlap attachments list in Larry skin (#1490479)
 - Fix so microseconds macro (u) in log_date_format works (#1490446)
 - Fix so unrecognized TNEF attachments are displayed on the list of attachments (#1490351)
+- Fix so database_attachments::cleanup() does not remove attachments from other sessions (#1490542)
 
 RELEASE 1.1.3
 -------------
diff --git a/plugins/database_attachments/database_attachments.php b/plugins/database_attachments/database_attachments.php
index 735915ae3..31747b35c 100644
--- a/plugins/database_attachments/database_attachments.php
+++ b/plugins/database_attachments/database_attachments.php
@@ -22,7 +22,7 @@ class database_attachments extends filesystem_attachments
     protected $cache;
 
     // A prefix for the cache key used in the session and in the key field of the cache table
-    protected $prefix = "db_attach";
+    const PREFIX = "ATTACH";
 
     /**
      * Save a newly uploaded attachment
@@ -153,9 +153,16 @@ class database_attachments extends filesystem_attachments
             $ttl    = 12 * 60 * 60; // default: 12 hours
             $ttl    = $rcmail->config->get('database_attachments_cache_ttl', $ttl);
             $type   = $rcmail->config->get('database_attachments_cache', 'db');
+            $prefix = self::PREFIX;
+
+            // Add session identifier to the prefix to prevent from removing attachments
+            // in other sessions of the same user (#1490542)
+            if ($id = session_id()) {
+                $prefix .= $id;
+            }
 
             // Init SQL cache (disable cache data serialization)
-            $this->cache = $rcmail->get_cache($this->prefix, $type, $ttl, false);
+            $this->cache = $rcmail->get_cache($prefix, $type, $ttl, false);
         }
 
         return $this->cache;
diff --git a/plugins/redundant_attachments/redundant_attachments.php b/plugins/redundant_attachments/redundant_attachments.php
index 17427f0d8..fc7e06e6d 100644
--- a/plugins/redundant_attachments/redundant_attachments.php
+++ b/plugins/redundant_attachments/redundant_attachments.php
@@ -36,7 +36,7 @@ require_once(RCUBE_PLUGINS_DIR . 'filesystem_attachments/filesystem_attachments.
 class redundant_attachments extends filesystem_attachments
 {
     // A prefix for the cache key used in the session and in the key field of the cache table
-    private $prefix = "ATTACH";
+    const PREFIX = "ATTACH";
 
     // rcube_cache instance for SQL DB
     private $cache;
@@ -46,13 +46,6 @@ class redundant_attachments extends filesystem_attachments
 
     private $loaded;
 
-    /**
-     * Default constructor
-     */
-    function init()
-    {
-        parent::init();
-    }
 
     /**
      * Loads plugin configuration and initializes cache object(s)
@@ -68,15 +61,20 @@ class redundant_attachments extends filesystem_attachments
         // load configuration
         $this->load_config();
 
-        $ttl = 12 * 60 * 60; // 12 hours
-        $ttl = $rcmail->config->get('redundant_attachments_cache_ttl', $ttl);
+        $ttl    = 12 * 60 * 60; // 12 hours
+        $ttl    = $rcmail->config->get('redundant_attachments_cache_ttl', $ttl);
+        $prefix = self::PREFIX;
+
+        if ($id = session_id()) {
+            $prefix .= $id;
+        }
 
         // Init SQL cache (disable cache data serialization)
-        $this->cache = $rcmail->get_cache($this->prefix, 'db', $ttl, false);
+        $this->cache = $rcmail->get_cache($prefix, 'db', $ttl, false);
 
         // Init memcache (fallback) cache
         if ($rcmail->config->get('redundant_attachments_memcache')) {
-            $this->mem_cache = $rcmail->get_cache($this->prefix, 'memcache', $ttl, false);
+            $this->mem_cache = $rcmail->get_cache($prefix, 'memcache', $ttl, false);
         }
 
         $this->loaded = true;