id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
1930	Space in URL %20 is decoded space causing an invalid URL	cawoodm@…		"We are seeing nginx 1.15 and the latest 1.17.8 wrongly decoding %20 to "" "" (space) in URLs before forwarding them upstream. Some upstreams do not accept this and cause a 400. Nginx should not IMHO be unencoding URLs!

Consider the following Nginx running on 8080 with fiddler running as the upstream server on port 8888 to view traffic:

{{{
location ~ ""^/yo/(.*)"" {
  proxy_pass http://127.0.0.1:8888/$1$is_args$args;
}
}}}


Next we hit NginX with:
{{{
GET http://localhost:8080/yo/foo%20bar
}}}

Fiddler (upstream) shows the incoming request as:
{{{
GET /foo bar
}}}

Correct would be
{{{
GET /foo%20bar
}}}

The following workaround is available:
{{{
location ~ ""^/yo/(.*)"" {
  set $allowspace1 $1;
  proxy_pass http://127.0.0.1:8888/$allowspace1$is_args$args;
}}}"	defect	closed	minor		documentation	1.17.x	invalid			Windows 10 64-bit	"nginx version: nginx/1.17.8
built by cl 16.00.40219.01 for 80x86
built with OpenSSL 1.1.1d  10 Sep 2019
TLS SNI support enabled
configure arguments: --with-cc=cl --builddir=objs.msvc8 --with-debug --prefix= --conf-path=conf/nginx.conf --pid-path=logs/nginx.pid --http-log-path=logs/access.log --error-log-path=logs/error.log --sbin-path=nginx.exe --http-client-body-temp-path=temp/client_body_temp --http-proxy-temp-path=temp/proxy_temp --http-fastcgi-temp-path=temp/fastcgi_temp --http-scgi-temp-path=temp/scgi_temp --http-uwsgi-temp-path=temp/uwsgi_temp --with-cc-opt=-DFD_SETSIZE=1024 --with-pcre=objs.msvc8/lib/pcre-8.43 --with-zlib=objs.msvc8/lib/zlib-1.2.11 --with-http_v2_module --with-http_realip_module --with-http_addition_module --with-http_sub_module --with-http_dav_module --with-http_stub_status_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_auth_request_module --with-http_random_index_module --with-http_secure_link_module --with-http_slice_module --with-mail --with-stream --with-openssl=objs.msvc8/lib/openssl-1.1.1d --with-openssl-opt='no-asm no-tests -D_WIN32_WINNT=0x0501' --with-http_ssl_module --with-mail_ssl_module --with-stream_ssl_module"