Index: django/contrib/staticfiles/management/commands/collectstatic.py
===================================================================
--- django/contrib/staticfiles/management/commands/collectstatic.py	(revision 15377)
+++ django/contrib/staticfiles/management/commands/collectstatic.py	(working copy)
@@ -115,6 +115,16 @@
         symlink = options['link']
         dry_run = options['dry_run']
 
+        if settings.STATIC_ROOT in settings.MEDIA_ROOT:
+            media_root = settings.MEDIA_ROOT.replace(settings.STATIC_ROOT, '')
+            if media_root.startswith('/'):
+                media_root = media_root[1:]
+
+        if destination.split('/')[0] == media_root:
+            msg = "Skipping '%s' (attempting to write to MEDIA_ROOT)"
+            self.log(msg % destination)
+            return False
+
         if destination in self.copied_files:
             self.log("Skipping '%s' (already copied earlier)" % destination)
             return False