diff --git a/mongoose.c b/mongoose.c
index 9571d574..5c800075 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -6289,7 +6289,7 @@ int mg_parse_http(const char *s, int n, struct http_message *hm, int is_req) {
     }
   } else {
     s = mg_skip(s, end, " ", &hm->proto);
-    if (end - s < 4 || s[3] != ' ') return -1;
+    if (end - s < 4 || s[0] < '0' || s[0] > '9' || s[3] != ' ') return -1;
     hm->resp_code = atoi(s);
     if (hm->resp_code < 100 || hm->resp_code >= 600) return -1;
     s += 4;
@@ -6590,6 +6590,7 @@ void mg_http_handler(struct mg_connection *nc, int ev,
       struct mg_http_multipart_part mp;
       memset(&mp, 0, sizeof(mp));
       mp.status = -1;
+      mp.user_data = pd->mp_stream.user_data;
       mp.var_name = pd->mp_stream.var_name;
       mp.file_name = pd->mp_stream.file_name;
       mg_call(nc, (pd->endpoint_handler ? pd->endpoint_handler : nc->handler),
diff --git a/src/mg_http.c b/src/mg_http.c
index ef546c37..2751d51d 100644
--- a/src/mg_http.c
+++ b/src/mg_http.c
@@ -455,7 +455,7 @@ int mg_parse_http(const char *s, int n, struct http_message *hm, int is_req) {
     }
   } else {
     s = mg_skip(s, end, " ", &hm->proto);
-    if (end - s < 4 || s[3] != ' ') return -1;
+    if (end - s < 4 || s[0] < '0' || s[0] > '9' || s[3] != ' ') return -1;
     hm->resp_code = atoi(s);
     if (hm->resp_code < 100 || hm->resp_code >= 600) return -1;
     s += 4;
@@ -756,6 +756,7 @@ void mg_http_handler(struct mg_connection *nc, int ev,
       struct mg_http_multipart_part mp;
       memset(&mp, 0, sizeof(mp));
       mp.status = -1;
+      mp.user_data = pd->mp_stream.user_data;
       mp.var_name = pd->mp_stream.var_name;
       mp.file_name = pd->mp_stream.file_name;
       mg_call(nc, (pd->endpoint_handler ? pd->endpoint_handler : nc->handler),
diff --git a/test/Makefile b/test/Makefile
index b3457bf9..7bf70a10 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -17,7 +17,7 @@ else
 COMMON_PARENT = $(SRC_DIR)
 endif
 
-TEST_SOURCES = unit_test.c test_util.c test_main.c
+TEST_SOURCES = unit_test.c test_util.c test_main.c fuzz.c
 AMALGAMATED_SOURCES = ../mongoose.c
 KRYPTON_PATH = $(REPO_ROOT)/krypton
 
@@ -118,6 +118,10 @@ clean_index_cgi:
 	@echo -e "CLEAN\tindex.cgi"
 	@rm -f data/cgi/index.cgi*
 
+fuzz:
+	$(CC) fuzz.c ../mongoose.c -o /tmp/$@ -fsanitize=fuzzer,address -g -I..
+	/tmp/$@
+
 # Interactive:
 #   docker run -v $(CURDIR)/../..:/cesanta -t -i --entrypoint=/bin/bash cesanta/mongoose_test
 docker:
diff --git a/test/fuzz.c b/test/fuzz.c
new file mode 100644
index 00000000..7a9b0df6
--- /dev/null
+++ b/test/fuzz.c
@@ -0,0 +1,8 @@
+#include "mongoose.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  struct http_message req;
+  mg_parse_http((const char *) data, size, &req, 0);
+  mg_parse_http((const char *) data, size, &req, 1);
+  return 0;
+}