Created attachment 33132 [details] Patch to correct the valid domain characters in Rfc6265CookieProcessor The list of valid characters for cookie domains in org.apache.tomcat.util.http.Rfc6265CookieProcessor is missing 'z', 'Z' and '9' due to an off-by-one-error.
Thanks for the report and the patch. The patch has been applied to trunk and 8.0.x for 8.0.27 onwards.