diff --git a/lib/conncache.c b/lib/conncache.c
index f98e22978..d21a00cfd 100644
--- a/lib/conncache.c
+++ b/lib/conncache.c
@@ -534,7 +534,7 @@ Curl_conncache_extract_oldest(struct Curl_easy *data)
 void Curl_conncache_close_all_connections(struct conncache *connc)
 {
   struct connectdata *conn;
-  char buffer[READBUFFER_MIN];
+  char buffer[READBUFFER_MIN + 1];
   if(!connc->closure_handle)
     return;
   connc->closure_handle->state.buffer = buffer;