diff --git a/src/burl.c b/src/burl.c
index fe999b21..1c3ff7bc 100644
--- a/src/burl.c
+++ b/src/burl.c
@@ -66,8 +66,8 @@ static int burl_normalize_basic_unreserved_fix (buffer *b, buffer *t, int i, int
     memcpy(p, s, (size_t)i);
     for (; i < used; ++i, ++j) {
         if (!encoded_chars_http_uri_reqd[s[i]]) {
-            if (s[i] == '?' && -1 == qs) qs = j;
             p[j] = s[i];
+            if (__builtin_expect( (s[i] == '?'), 0) && -1 == qs) qs = j;
         }
         else if (s[i]=='%' && li_cton(s[i+1], n1) && li_cton(s[i+2], n2)) {
             const unsigned int x = (n1 << 4) | n2;
@@ -104,7 +104,7 @@ static int burl_normalize_basic_unreserved (buffer *b, buffer *t)
 
     for (int i = 0; i < used; ++i) {
         if (!encoded_chars_http_uri_reqd[s[i]]) {
-            if (s[i] == '?' && -1 == qs) qs = i;
+            if (__builtin_expect( (s[i] == '?'), 0) && -1 == qs) qs = i;
         }
         else if (s[i]=='%' && li_cton(s[i+1], n1) && li_cton(s[i+2], n2)
                  && !burl_is_unreserved((x = (n1 << 4) | n2))) {
@@ -135,11 +135,12 @@ static int burl_normalize_basic_required_fix (buffer *b, buffer *t, int i, int q
     unsigned char * const p =
       (unsigned char *)buffer_string_prepare_copy(t,i+(used-i)*3+1);
     unsigned int n1, n2;
+    int invalid_utf8 = 0;
     memcpy(p, s, (size_t)i);
     for (; i < used; ++i, ++j) {
         if (!encoded_chars_http_uri_reqd[s[i]]) {
-            if (s[i] == '?' && -1 == qs) qs = j;
             p[j] = s[i];
+            if (__builtin_expect( (s[i] == '?'), 0)) qs = j;
         }
         else if (s[i]=='%' && li_cton(s[i+1], n1) && li_cton(s[i+2], n2)) {
             const unsigned int x = (n1 << 4) | n2;
@@ -153,7 +154,7 @@ static int burl_normalize_basic_required_fix (buffer *b, buffer *t, int i, int q
                 p[j]   = '%';
                 p[++j] = hex_chars_uc[n1]; /*(s[i+1] & 0xdf)*/
                 p[++j] = hex_chars_uc[n2]; /*(s[i+2] & 0xdf)*/
-                if (li_utf8_invalid_byte(x)) qs = -2;
+                invalid_utf8 |= li_utf8_invalid_byte(x);
             }
             i+=2;
         }
@@ -162,11 +163,11 @@ static int burl_normalize_basic_required_fix (buffer *b, buffer *t, int i, int q
             p[j]   = '%';
             p[++j] = hex_chars_uc[(s[i] >> 4) & 0xF];
             p[++j] = hex_chars_uc[s[i] & 0xF];
-            if (li_utf8_invalid_byte(s[i])) qs = -2;
+            invalid_utf8 |= li_utf8_invalid_byte(s[i]);
         }
     }
     buffer_copy_string_len(b, (char *)p, (size_t)j);
-    return qs;
+    return !invalid_utf8 ? qs : -2;
 }
 
 
@@ -176,17 +177,18 @@ static int burl_normalize_basic_required (buffer *b, buffer *t)
     const int used = (int)buffer_clen(b);
     unsigned int n1, n2, x;
     int qs = -1;
+    int invalid_utf8 = 0;
 
     for (int i = 0; i < used; ++i) {
         if (!encoded_chars_http_uri_reqd[s[i]]) {
-            if (s[i] == '?' && -1 == qs) qs = i;
+            if (s[i] == '?') qs = i;
         }
         else if (s[i]=='%' && li_cton(s[i+1], n1) && li_cton(s[i+2], n2)
                  && (encoded_chars_http_uri_reqd[(x = (n1 << 4) | n2)]
                      || (qs < 0
                          ? (x == '/' || x == '?')
                          : (x == '&' || x == '=' || x == ';' || x == '+')))) {
-            if (li_utf8_invalid_byte(x)) qs = -2;
+            invalid_utf8 |= li_utf8_invalid_byte(x);
             if (s[i+1] >= 'a') b->ptr[i+1] &= 0xdf; /* uppercase hex */
             if (s[i+2] >= 'a') b->ptr[i+2] &= 0xdf; /* uppercase hex */
             i+=2;
@@ -201,7 +203,7 @@ static int burl_normalize_basic_required (buffer *b, buffer *t)
         }
     }
 
-    return qs;
+    return !invalid_utf8 ? qs : -2;
 }
 
 
@@ -323,6 +325,15 @@ static int burl_normalize_path (buffer *b, buffer *t, int qs, int flags)
 }
 
 
+__attribute_cold__
+__attribute_noinline__
+__attribute_pure__
+static int burl_scan_qmark (const buffer * const b) {
+    const char * const qmark = strchr(b->ptr, '?');
+    return qmark ? (int)(qmark - b->ptr) : -1;
+}
+
+
 int burl_normalize (buffer *b, buffer *t, int flags)
 {
     int qs;
@@ -342,7 +353,10 @@ int burl_normalize (buffer *b, buffer *t, int flags)
     qs = (flags & HTTP_PARSEOPT_URL_NORMALIZE_REQUIRED)
       ? burl_normalize_basic_required(b, t)
       : burl_normalize_basic_unreserved(b, t);
-    if (-2 == qs) return -2;
+    if (-2 == qs) {
+        if (flags & HTTP_PARSEOPT_URL_NORMALIZE_INVALID_UTF8_REJECT) return -2;
+        qs = burl_scan_qmark(b);
+    }
 
     if (flags & HTTP_PARSEOPT_URL_NORMALIZE_CTRLS_REJECT) {
         if (burl_contains_ctrls(b)) return -2;
diff --git a/src/burl.h b/src/burl.h
index a013cc07..2d66f192 100644
--- a/src/burl.h
+++ b/src/burl.h
@@ -26,6 +26,7 @@ enum burl_opts_e {
  ,HTTP_PARSEOPT_URL_NORMALIZE_PATH_DOTSEG_REMOVE  =0x400/* "." ".." "//" */
  ,HTTP_PARSEOPT_URL_NORMALIZE_PATH_DOTSEG_REJECT  =0x800
  ,HTTP_PARSEOPT_URL_NORMALIZE_QUERY_20_PLUS       =0x1000
+ ,HTTP_PARSEOPT_URL_NORMALIZE_INVALID_UTF8_REJECT =0x2000
  ,HTTP_PARSEOPT_METHOD_GET_BODY                   =0x8000
 };
 
diff --git a/src/configfile.c b/src/configfile.c
index 23cb8d06..1961ff33 100644
--- a/src/configfile.c
+++ b/src/configfile.c
@@ -574,6 +574,8 @@ static int config_http_parseopts (server *srv, const array *a) {
             opt = HTTP_PARSEOPT_URL_NORMALIZE_PATH_DOTSEG_REJECT;
         else if (buffer_eq_slen(k, CONST_STR_LEN("url-query-20-plus")))
             opt = HTTP_PARSEOPT_URL_NORMALIZE_QUERY_20_PLUS;
+        else if (buffer_eq_slen(k, CONST_STR_LEN("url-invalid-utf8-reject")))
+            opt = HTTP_PARSEOPT_URL_NORMALIZE_INVALID_UTF8_REJECT;
         else if (buffer_eq_slen(k, CONST_STR_LEN("header-strict"))) {
             srv->srvconf.http_header_strict = val;
             continue;
@@ -631,7 +633,8 @@ static int config_http_parseopts (server *srv, const array *a) {
         }
         if (!(opts & (HTTP_PARSEOPT_URL_NORMALIZE_UNRESERVED
                      |HTTP_PARSEOPT_URL_NORMALIZE_REQUIRED))) {
-            opts |= HTTP_PARSEOPT_URL_NORMALIZE_UNRESERVED;
+            opts |= HTTP_PARSEOPT_URL_NORMALIZE_UNRESERVED
+                 |  HTTP_PARSEOPT_URL_NORMALIZE_INVALID_UTF8_REJECT;
             if (decode_2f
                 && !(opts & HTTP_PARSEOPT_URL_NORMALIZE_PATH_2F_REJECT))
                 opts |= HTTP_PARSEOPT_URL_NORMALIZE_PATH_2F_DECODE;
@@ -1521,7 +1524,8 @@ void config_init(server *srv) {
       | HTTP_PARSEOPT_URL_NORMALIZE_UNRESERVED
       | HTTP_PARSEOPT_URL_NORMALIZE_CTRLS_REJECT
       | HTTP_PARSEOPT_URL_NORMALIZE_PATH_2F_DECODE
-      | HTTP_PARSEOPT_URL_NORMALIZE_PATH_DOTSEG_REMOVE;
+      | HTTP_PARSEOPT_URL_NORMALIZE_PATH_DOTSEG_REMOVE
+      | HTTP_PARSEOPT_URL_NORMALIZE_INVALID_UTF8_REJECT;
 
     srv->srvconf.modules = array_init(16);
     srv->srvconf.modules_dir = LIBRARY_DIR;
diff --git a/src/t/test_burl.c b/src/t/test_burl.c
index 174d1c3c..fa9190ff 100644
--- a/src/t/test_burl.c
+++ b/src/t/test_burl.c
@@ -31,6 +31,11 @@ static void test_burl_normalize (void) {
     int flags;
 
     flags = HTTP_PARSEOPT_URL_NORMALIZE_UNRESERVED;
+    run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/%C0"), CONST_STR_LEN("/%C0"));
+    run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/\377"), CONST_STR_LEN("/%FF"));
+
+    flags = HTTP_PARSEOPT_URL_NORMALIZE_UNRESERVED
+          | HTTP_PARSEOPT_URL_NORMALIZE_INVALID_UTF8_REJECT;
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("no-slash"), CONST_STR_LEN("no-slash"));
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/"), CONST_STR_LEN("/"));
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/abc"), CONST_STR_LEN("/abc"));
@@ -53,11 +58,13 @@ static void test_burl_normalize (void) {
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/%3a"), CONST_STR_LEN("/%3A"));
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/%3A"), CONST_STR_LEN("/%3A"));
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/~test%20ä_"), CONST_STR_LEN("/~test%20%C3%A4_"));
+    run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/%C0"),  "", (size_t)-2);
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/\375"), "", (size_t)-2);
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/\376"), "", (size_t)-2);
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/\377"), "", (size_t)-2);
 
-    flags = HTTP_PARSEOPT_URL_NORMALIZE_REQUIRED;
+    flags = HTTP_PARSEOPT_URL_NORMALIZE_REQUIRED
+          | HTTP_PARSEOPT_URL_NORMALIZE_INVALID_UTF8_REJECT;
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/"), CONST_STR_LEN("/"));
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/abc"), CONST_STR_LEN("/abc"));
     run_burl_normalize(psrc, ptmp, flags, __LINE__, CONST_STR_LEN("/abc/"), CONST_STR_LEN("/abc/"));