A recent Apache update unexpectedly fixed a problem where mod_rewrite did not properly escape URIs when following the proxy rule [P].

Some sites have worked around this problem by using the global RewriteMap "escaped", like so:

RewriteRule (.) http://cloud.9/${escaped:$1} [P]

Since the update, sites that use this RewriteMap will escape URIs twice, resulting in a malformed URI sent from the proxy to the final server.  If you use the "escaped" RewriteMap through mod_rewrite, please check that your site works properly with proxy URLs containing special chars (such as a space or colon).

Proxy rewrite rules should be modified to work without the "escape" RewriteMap:

RewriteRule (.) http://cloud.9/$1 [P]