diff --git a/include/haproxy/qmux_http.h b/include/haproxy/qmux_http.h
index a7dbe7cc3..4a7711401 100644
--- a/include/haproxy/qmux_http.h
+++ b/include/haproxy/qmux_http.h
@@ -10,7 +10,6 @@ size_t qcs_http_rcv_buf(struct qcs *qcs, struct buffer *buf, size_t count,
                         char *fin);
 size_t qcs_http_snd_buf(struct qcs *qcs, struct buffer *buf, size_t count,
                         char *fin);
-size_t qcs_http_reset_buf(struct qcs *qcs, struct buffer *buf, size_t count);
 
 #endif /* USE_QUIC */
 
diff --git a/src/mux_quic.c b/src/mux_quic.c
index bf3616e0c..21b1cdec7 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -2811,6 +2811,9 @@ static size_t qmux_strm_snd_buf(struct stconn *sc, struct buffer *buf,
 
 	TRACE_ENTER(QMUX_EV_STRM_SEND, qcs->qcc->conn, qcs);
 
+	/* Sending forbidden if QCS is locally closed (FIN or RESET_STREAM sent). */
+	BUG_ON(qcs_is_close_local(qcs) || (qcs->flags & QC_SF_TO_RESET));
+
 	/* stream layer has been detached so no transfer must occur after. */
 	BUG_ON_HOT(qcs->flags & QC_SF_DETACH);
 
@@ -2821,11 +2824,6 @@ static size_t qmux_strm_snd_buf(struct stconn *sc, struct buffer *buf,
 		goto end;
 	}
 
-	if (qcs_is_close_local(qcs) || (qcs->flags & QC_SF_TO_RESET)) {
-		ret = qcs_http_reset_buf(qcs, buf, count);
-		goto end;
-	}
-
 	ret = qcs_http_snd_buf(qcs, buf, count, &fin);
 	if (fin) {
 		TRACE_STATE("reached stream fin", QMUX_EV_STRM_SEND, qcs->qcc->conn, qcs);
@@ -2853,6 +2851,9 @@ static size_t qmux_strm_nego_ff(struct stconn *sc, struct buffer *input,
 
 	TRACE_ENTER(QMUX_EV_STRM_SEND, qcs->qcc->conn, qcs);
 
+	/* Sending forbidden if QCS is locally closed (FIN or RESET_STREAM sent). */
+	BUG_ON(qcs_is_close_local(qcs) || (qcs->flags & QC_SF_TO_RESET));
+
 	/* stream layer has been detached so no transfer must occur after. */
 	BUG_ON_HOT(qcs->flags & QC_SF_DETACH);
 
diff --git a/src/qmux_http.c b/src/qmux_http.c
index 3c5f3917c..092eb15da 100644
--- a/src/qmux_http.c
+++ b/src/qmux_http.c
@@ -95,23 +95,3 @@ size_t qcs_http_snd_buf(struct qcs *qcs, struct buffer *buf, size_t count,
 
 	return ret;
 }
-
-/* QUIC MUX snd_buf reset. HTX data stored in <buf> of length <count> will be
- * cleared. This can be used when data should not be transmitted any longer.
- *
- * Return the size in bytes of cleared data.
- */
-size_t qcs_http_reset_buf(struct qcs *qcs, struct buffer *buf, size_t count)
-{
-	struct htx *htx;
-
-	TRACE_ENTER(QMUX_EV_STRM_SEND, qcs->qcc->conn, qcs);
-
-	htx = htx_from_buf(buf);
-	htx_reset(htx);
-	htx_to_buf(htx, buf);
-
-	TRACE_LEAVE(QMUX_EV_STRM_SEND, qcs->qcc->conn, qcs);
-
-	return count;
-}