diff --git a/mongoose.c b/mongoose.c
index 36f02329..01926fd5 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -1998,6 +1998,8 @@ int mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
 }
 
 int mg_iobuf_init(struct mg_iobuf *io, size_t size) {
+  io->buf = NULL;
+  io->size = io->len = 0;
   return mg_iobuf_resize(io, size);
 }
 
diff --git a/src/iobuf.c b/src/iobuf.c
index 03185fe4..f1f2db02 100644
--- a/src/iobuf.c
+++ b/src/iobuf.c
@@ -38,6 +38,8 @@ int mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
 }
 
 int mg_iobuf_init(struct mg_iobuf *io, size_t size) {
+  io->buf = NULL;
+  io->size = io->len = 0;
   return mg_iobuf_resize(io, size);
 }