Wildfly 21's “allow-unescaped-characters-in-url” ignored when HTTP2 request going through Windows hosts file ------------------------------------------------------------------------------------------------------------ Key: WFLY-14269 URL: https://issues.redhat.com/browse/WFLY-14269 Project: WildFly Issue Type: Bug Components: Web (Undertow) Affects Versions: 21.0.0.Final, 21.0.1.Final, 21.0.2.Final Reporter: Marton Csukas Assignee: Flavia Rainone Priority: Major I have a _Wildfly 21.0.0.Final_ running a Spring Boot REST application and I encountered a strange behaviour with {{GET}} requests containing {{|}} (pipe) character in the query parameters. {{|}} (pipe) character is unsafe according to the RFC1738 specification of HTTP, while RFC3986 allows for the encoding of Unicode characters. However, Wildfly (Undertow) has an option on {{http-listener}} and {{https-listener}} entries to {{allow-unescaped-characters-in-url}}. Full {{standalone.xml}} [here|https://gist.github.com/martoncsukas/746695... masked sensitive info.   The application is running on {{127.0.0.1:443}}, and is exposed to the outside world as [https://myappname.company.com|https://myappname.company.com/] via a PulseSecure load balancer, where {{myappname}} is a CNAME registered on {{company.com}} DNS, pointing to the load balancers VIP. The {{allow-unescaped-characters-in-url="true"}} bit works fine in these cases (so when the request containing {{|}} _doesn't_ go through the Windows {{hosts}} file, but goes through the load balancer). However, when I add an entry to the Windows {{hosts}} file to bypass the load balancer, such as:  127.0.0.1 myappname.company.com …then the {{GET}} request containing {{|}} in its query parameter won't work - in fact it looks like it is not even hitting the server, as if Wildfly/Undertow's {{allow-unescaped-characters-in-url="true"}} setting wouldn't even be there. Now this causes issues with our local testing. Is there any change we can make so that {{allow-unescaped-characters-in-url="true"}} would be always respected? We know that ideally {{|}} should be encoded to {{%7D}}, but we would be interested in a solution (ideally on Wildfly level) that would make {{allow-unescaped-characters-in-url="true"}} work every time, irrespective whether the requests is going through {{hosts}} file or the load balancer. The very strange this is that it was working fine in _Wildfly 20.0.0.Final_, even without {{allow-unescaped-characters-in-url="true"}} being in {{standalone.xml}}.   Full request source: {code:java} GET /rest/v3/news/_lite?mql=customerId=1212090,caseId=1078841||caseId=null HTTP/1.1 Host: myappname.company.com Connection: keep-alive Pragma: no-cache Cache-Control: no-cache sec-ch-ua: "Google Chrome";v="87", " Not;A Brand";v="99", "Chromium";v="87" Accept: application/json, text/plain, */* Authorization: Bearer masked sec-ch-ua-mobile: ?0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36 Sec-Fetch-Site: same-origin Sec-Fetch-Mode: cors Sec-Fetch-Dest: empty Referer: https://myappname.company.com/anotherPage Accept-Encoding: gzip, deflate, br Accept-Language: en-GB,en;q=0.9 Cookie: JSESSIONID=masked; _ga=GA1.2.1926489359.1609961117; _gid=masked; _gat_gtag_UA_112487518_3=1{code}