diff --git a/core/modules/system/system.base.css b/core/modules/system/system.base.css
index 8519362..45a63c3 100644
--- a/core/modules/system/system.base.css
+++ b/core/modules/system/system.base.css
@@ -38,6 +38,14 @@ html.js input.throbbing {
   background-position: 100% -18px; /* LTR */
 }
 
+/** Prevent input forms from overflowing
+ *
+ *  @see http://drupal.org/node/869444
+ */
+input {
+  max-width: 100%;
+}
+
 /**
  * Collapsible fieldsets.
  *