diff --git a/dev/codesniffer/ruleset.dtd b/dev/codesniffer/ruleset.dtd
index e307d564e12..276626a3a16 100644
--- a/dev/codesniffer/ruleset.dtd
+++ b/dev/codesniffer/ruleset.dtd
@@ -3,6 +3,7 @@
 <!ATTLIST ruleset name CDATA "">
 <!ELEMENT description (#PCDATA)>
 <!ELEMENT exclude-pattern (#PCDATA)>
+<!ATTLIST exclude-pattern type CDATA "">
 <!ELEMENT rule (properties*,severity*)>
 <!ATTLIST rule ref CDATA "">
 <!ELEMENT properties (property+)>