diff --git a/src/h3.c b/src/h3.c
index 48bf6d8de..06d954ebc 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -938,8 +938,8 @@ static ssize_t h3_headers_to_htx(struct qcs *qcs, const struct buffer *buf,
 	if (htx)
 		htx_to_buf(htx, &htx_buf);
 
-	/* buffer is transferred to the stream connector and set to NULL
-	 * except on stream creation error.
+	/* Buffer is transferred to the stream connector and set to NULL except
+	 * on stream creation error or QCS already fully closed.
 	 */
 	if (b_size(&htx_buf)) {
 		b_free(&htx_buf);
diff --git a/src/mux_quic.c b/src/mux_quic.c
index 5ff006090..6e5cad01a 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -899,7 +899,12 @@ void qcs_send_metadata(struct qcs *qcs)
  * the first received request data. <fin> must be set if the whole request is
  * already received.
  *
- * Returns 0 on success else a negative error code.
+ * Note that if <qcs> is already fully closed, no streamdesc is instantiated.
+ * This is useful if a RESET_STREAM was already emitted in response to a
+ * STOP_SENDING.
+ *
+ * Returns 0 on success else a negative error code. If stream is already fully
+ * closed and nothing is performed, it is considered as a success case.
  */
 int qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin)
 {
@@ -908,6 +913,11 @@ int qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin)
 
 	TRACE_ENTER(QMUX_EV_STRM_RECV, qcc->conn, qcs);
 
+	if (qcs->st == QC_SS_CLO) {
+		TRACE_STATE("skip attach on already closed stream", QMUX_EV_STRM_RECV, qcc->conn, qcs);
+		goto out;
+	}
+
 	/* TODO duplicated from mux_h2 */
 	sess->t_idle = ns_to_ms(now_ns - sess->accept_ts) - sess->t_handshake;
 
@@ -958,6 +968,7 @@ int qcs_attach_sc(struct qcs *qcs, struct buffer *buf, char fin)
 		se_fl_set_error(qcs->sd);
 	}
 
+ out:
 	TRACE_LEAVE(QMUX_EV_STRM_RECV, qcc->conn, qcs);
 	return 0;
 }
@@ -1152,7 +1163,7 @@ static int qcc_decode_qcs(struct qcc *qcc, struct qcs *qcs)
 	if (qcs_is_close_remote(qcs))
 		fin = 1;
 
-	if (!(qcs->flags & QC_SF_READ_ABORTED) && !qcs_is_completed(qcs)) {
+	if (!(qcs->flags & QC_SF_READ_ABORTED)) {
 		ret = qcc->app_ops->rcv_buf(qcs, &b, fin);
 
 		if (qcc->glitches != prev_glitches)