diff --git a/include/haproxy/mux_quic.h b/include/haproxy/mux_quic.h
index bfdf4dd1c..8b2444ccc 100644
--- a/include/haproxy/mux_quic.h
+++ b/include/haproxy/mux_quic.h
@@ -21,7 +21,7 @@ void qcc_set_error(struct qcc *qcc, int err, int app);
 int _qcc_report_glitch(struct qcc *qcc, int inc);
 struct qcs *qcc_init_stream_local(struct qcc *qcc, int bidi);
 void qcs_send_metadata(struct qcs *qcs);
-struct stconn *qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin);
+int qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin);
 int qcs_is_close_local(struct qcs *qcs);
 int qcs_is_close_remote(struct qcs *qcs);
 
diff --git a/src/h3.c b/src/h3.c
index 9f7bb0206..48bf6d8de 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -915,7 +915,7 @@ static ssize_t h3_headers_to_htx(struct qcs *qcs, const struct buffer *buf,
 	htx_to_buf(htx, &htx_buf);
 	htx = NULL;
 
-	if (!qcs_attach_sc(qcs, &htx_buf, fin)) {
+	if (qcs_attach_sc(qcs, &htx_buf, fin)) {
 		len = -1;
 		goto out;
 	}
diff --git a/src/hq_interop.c b/src/hq_interop.c
index 18e9e2ccc..1d7821fec 100644
--- a/src/hq_interop.c
+++ b/src/hq_interop.c
@@ -77,7 +77,7 @@ static ssize_t hq_interop_rcv_buf(struct qcs *qcs, struct buffer *b, int fin)
 	htx->flags |= HTX_FL_EOM;
 	htx_to_buf(htx, &htx_buf);
 
-	if (!qcs_attach_sc(qcs, &htx_buf, fin))
+	if (qcs_attach_sc(qcs, &htx_buf, fin))
 		return -1;
 
 	b_free(&htx_buf);
diff --git a/src/mux_quic.c b/src/mux_quic.c
index dac22af35..5ff006090 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -899,9 +899,9 @@ void qcs_send_metadata(struct qcs *qcs)
  * the first received request data. <fin> must be set if the whole request is
  * already received.
  *
- * Returns the newly allocated instance on success or NULL on error.
+ * Returns 0 on success else a negative error code.
  */
-struct stconn *qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin)
+int qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin)
 {
 	struct qcc *qcc = qcs->qcc;
 	struct session *sess = qcc->conn->owner;
@@ -913,7 +913,7 @@ struct stconn *qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin)
 
 	if (!sc_new_from_endp(qcs->sd, sess, buf)) {
 		TRACE_DEVEL("leaving on error", QMUX_EV_STRM_RECV, qcc->conn, qcs);
-		return NULL;
+		return -1;
 	}
 
 	/* QC_SF_HREQ_RECV must be set once for a stream. Else, nb_hreq counter
@@ -959,7 +959,7 @@ struct stconn *qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin)
 	}
 
 	TRACE_LEAVE(QMUX_EV_STRM_RECV, qcc->conn, qcs);
-	return qcs->sd->sc;
+	return 0;
 }
 
 /* Use this function for a stream <id> which is not in <qcc> stream tree. It