--- jakarta-tomcat-catalina/catalina/src/share/org/apache/coyote/tomcat5/CoyoteRequest.java	2004-11-24 17:55:18.000000000 +0100
+++ jakarta-tomcat-catalina/catalina/src/share/org/apache/coyote/tomcat5/CoyoteRequest.java	2008-04-04 15:35:26.000000000 +0200
@@ -2539,6 +2539,9 @@
                     variant = "";
                 }
             }
+            if (!isAlpha(language) || !isAlpha(country) || !isAlpha(variant)) {
+                continue;
+            }
 
             // Add a new Locale to the list of Locales for this quality level
             Locale locale = new Locale(language, country, variant);
@@ -2604,4 +2607,14 @@
 
     }
 
+    protected static final boolean isAlpha(String value) {
+        for (int i = 0; i < value.length(); i++) {
+            char c = value.charAt(i);
+            if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
 }