--- mod_proxy.c	(revision 643170)
+++ mod_proxy.c	(working copy)
@@ -507,8 +507,20 @@ 
                     mismatch = 1;
                     use_uri = r->uri;
                 }
-                found = apr_pstrcat(r->pool, "proxy:", ent[i].real,
-                                    use_uri + len, NULL);
+
+                struct iovec args[3];
+                args[0].iov_base = "proxy:";      args[0].iov_len = 6;
+                args[1].iov_base = (char *)ent[i].real;   args[1].iov_len = strlen(ent[i].real);
+                args[2].iov_base = (char *)use_uri + len; args[2].iov_len = strlen(use_uri + len);
+
+                if (use_uri == r->unparsed_uri) {
+                    /* unparsed_uri has queries, so we need to remove it */
+                    char *qmark = strchr(r->unparsed_uri, '?');
+                    if (qmark != NULL) {
+                        args[2].iov_len -= strlen(qmark);
+                    }
+                }
+                found = apr_pstrcatv(r->pool, (const struct iovec *)&args, 3, NULL);
             }
         }
         if (mismatch) {