diff --git a/docs/README.md b/docs/README.md
index 4d877a4a..9bae268b 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -528,21 +528,23 @@ by `buf`, and `len` specifies number of bytes currently stored.
 ### mg\_iobuf\_init()
 
 ```c
-void mg_iobuf_init(struct mg_iobuf *io, size_t size);
+int mg_iobuf_init(struct mg_iobuf *io, size_t size);
 ```
 
-Initialise IO buffer, allocate `size` bytes.
+Initialise IO buffer, allocate `size` bytes. Return 1 on success,
+0 on allocation failure.
 
 
 ### mg\_iobuf\_resize()
 
 ```c
-void mg_iobuf_resize(struct mg_iobuf *io, size_t size);
+int mg_iobuf_resize(struct mg_iobuf *io, size_t size);
 ```
 
 Resize IO buffer, set the new size to `size`. The `io->buf` pointer could
 change after this, for example if the buffer grows. If `size` is 0, then the
 `io->buf` is freed and set to NULL, and both `size` and `len` are set to 0.
+Return 1 on success, 0 on allocation failure.
 
 
 ### mg\_iobuf\_free()
diff --git a/mongoose.c b/mongoose.c
index 938766cf..9c386d89 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -1195,7 +1195,8 @@ struct mg_connection *mg_http_listen(struct mg_mgr *mgr, const char *url,
 
 #include <string.h>
 
-void mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
+int mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
+  int ok = 1;
   if (new_size == 0) {
     free(io->buf);
     io->buf = NULL;
@@ -1210,16 +1211,20 @@ void mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
       io->buf = (unsigned char *) p;
       io->size = new_size;
     } else {
+      ok = 0;
       LOG(LL_ERROR,
           ("%lu->%lu", (unsigned long) io->size, (unsigned long) new_size));
     }
   }
+  return ok;
 }
 
-void mg_iobuf_init(struct mg_iobuf *io, size_t size) {
+int mg_iobuf_init(struct mg_iobuf *io, size_t size) {
+  int ok = 1;
   io->buf = NULL;
   io->len = io->size = 0;
-  if (size > 0) mg_iobuf_resize(io, size);
+  if (size > 0) ok = mg_iobuf_resize(io, size);
+  return ok;
 }
 
 size_t mg_iobuf_append(struct mg_iobuf *io, const void *buf, size_t len,
@@ -2622,6 +2627,7 @@ int mg_send(struct mg_connection *c, const void *buf, size_t len) {
   int fail, n = c->is_udp
                     ? ll_write(c, buf, (SOCKET) len, &fail)
                     : (int) mg_iobuf_append(&c->send, buf, len, MG_IO_SIZE);
+  if (len > 0 && n == 0) fail = 1;
   return n;
 }
 
@@ -2696,8 +2702,9 @@ static void read_conn(struct mg_connection *c,
   // NOTE(lsm): do only one iteration of reads, cause some systems
   // (e.g. FreeRTOS stack) return 0 instead of -1/EWOULDBLOCK when no data
   if (c->recv.size - c->recv.len < MG_IO_SIZE &&
-      c->recv.size < MG_MAX_RECV_BUF_SIZE) {
-    mg_iobuf_resize(&c->recv, c->recv.size + MG_IO_SIZE);
+      c->recv.size < MG_MAX_RECV_BUF_SIZE &&
+      !mg_iobuf_resize(&c->recv, c->recv.size + MG_IO_SIZE)) {
+    c->is_closing = 1;
   }
   buf = c->recv.buf + c->recv.len;
   len = (int) (c->recv.size - c->recv.len);
diff --git a/mongoose.h b/mongoose.h
index 61114449..fdbdf95f 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -516,8 +516,8 @@ struct mg_iobuf {
   size_t size, len;
 };
 
-void mg_iobuf_init(struct mg_iobuf *, size_t);
-void mg_iobuf_resize(struct mg_iobuf *, size_t);
+int mg_iobuf_init(struct mg_iobuf *, size_t);
+int mg_iobuf_resize(struct mg_iobuf *, size_t);
 void mg_iobuf_free(struct mg_iobuf *);
 size_t mg_iobuf_append(struct mg_iobuf *, const void *, size_t, size_t);
 size_t mg_iobuf_delete(struct mg_iobuf *, size_t);
diff --git a/src/iobuf.c b/src/iobuf.c
index e7d1968c..f5eb61bf 100644
--- a/src/iobuf.c
+++ b/src/iobuf.c
@@ -3,7 +3,8 @@
 
 #include <string.h>
 
-void mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
+int mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
+  int ok = 1;
   if (new_size == 0) {
     free(io->buf);
     io->buf = NULL;
@@ -18,16 +19,20 @@ void mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
       io->buf = (unsigned char *) p;
       io->size = new_size;
     } else {
+      ok = 0;
       LOG(LL_ERROR,
           ("%lu->%lu", (unsigned long) io->size, (unsigned long) new_size));
     }
   }
+  return ok;
 }
 
-void mg_iobuf_init(struct mg_iobuf *io, size_t size) {
+int mg_iobuf_init(struct mg_iobuf *io, size_t size) {
+  int ok = 1;
   io->buf = NULL;
   io->len = io->size = 0;
-  if (size > 0) mg_iobuf_resize(io, size);
+  if (size > 0) ok = mg_iobuf_resize(io, size);
+  return ok;
 }
 
 size_t mg_iobuf_append(struct mg_iobuf *io, const void *buf, size_t len,
diff --git a/src/iobuf.h b/src/iobuf.h
index c3306464..a9683f25 100644
--- a/src/iobuf.h
+++ b/src/iobuf.h
@@ -7,8 +7,8 @@ struct mg_iobuf {
   size_t size, len;
 };
 
-void mg_iobuf_init(struct mg_iobuf *, size_t);
-void mg_iobuf_resize(struct mg_iobuf *, size_t);
+int mg_iobuf_init(struct mg_iobuf *, size_t);
+int mg_iobuf_resize(struct mg_iobuf *, size_t);
 void mg_iobuf_free(struct mg_iobuf *);
 size_t mg_iobuf_append(struct mg_iobuf *, const void *, size_t, size_t);
 size_t mg_iobuf_delete(struct mg_iobuf *, size_t);
diff --git a/src/sock.c b/src/sock.c
index 620daba7..f3e75055 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -161,6 +161,7 @@ int mg_send(struct mg_connection *c, const void *buf, size_t len) {
   int fail, n = c->is_udp
                     ? ll_write(c, buf, (SOCKET) len, &fail)
                     : (int) mg_iobuf_append(&c->send, buf, len, MG_IO_SIZE);
+  if (len > 0 && n == 0) fail = 1;
   return n;
 }
 
@@ -235,8 +236,9 @@ static void read_conn(struct mg_connection *c,
   // NOTE(lsm): do only one iteration of reads, cause some systems
   // (e.g. FreeRTOS stack) return 0 instead of -1/EWOULDBLOCK when no data
   if (c->recv.size - c->recv.len < MG_IO_SIZE &&
-      c->recv.size < MG_MAX_RECV_BUF_SIZE) {
-    mg_iobuf_resize(&c->recv, c->recv.size + MG_IO_SIZE);
+      c->recv.size < MG_MAX_RECV_BUF_SIZE &&
+      !mg_iobuf_resize(&c->recv, c->recv.size + MG_IO_SIZE)) {
+    c->is_closing = 1;
   }
   buf = c->recv.buf + c->recv.len;
   len = (int) (c->recv.size - c->recv.len);