diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index c0c3acc..d8c1e65 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1379,7 +1379,10 @@
     self->pos = 0;
     self->raw_pos = 0;
     self->read_end = 0;
-    while (self->read_end < self->buffer_size) {
+    /* NOTE: when the read is satisfied, we avoid issuing any additional
+       reads, which could block indefinitely (e.g. on a socket).
+       See issue #9550. */
+    while (remaining > 0 && self->read_end < self->buffer_size) {
         Py_ssize_t r = _bufferedreader_fill_buffer(self);
         if (r == -1)
             goto error;