From 704e7a85f39e8727876c53c601210258cb52774e Mon Sep 17 00:00:00 2001
From: Stefan Eissing <stefan@eissing.org>
Date: Fri, 6 Mar 2026 08:38:03 +0100
Subject: [PATCH] mqtt: fix EOF handling

In mqtt_recv_atleast(), recognize an EOF as error.

Fixes #20815
Reported-by: Max Dymond
Closes #20830
---
 lib/mqtt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/mqtt.c b/lib/mqtt.c
index ef373c0638..e591cfcf01 100644
--- a/lib/mqtt.c
+++ b/lib/mqtt.c
@@ -379,6 +379,8 @@ static CURLcode mqtt_recv_atleast(struct Curl_easy *data, size_t nbytes)
     result = Curl_xfer_recv(data, (char *)readbuf, nbytes - rlen, &nread);
     if(result)
       return result;
+    if(!nread) /* EOF */
+       return CURLE_RECV_ERROR;
     if(curlx_dyn_addn(&mq->recvbuf, readbuf, nread))
       return CURLE_OUT_OF_MEMORY;
     rlen = curlx_dyn_len(&mq->recvbuf);