diff --git a/include/haproxy/proto_quic.h b/include/haproxy/proto_quic.h
index b6f473c6d..1da8da8fe 100644
--- a/include/haproxy/proto_quic.h
+++ b/include/haproxy/proto_quic.h
@@ -30,4 +30,6 @@ extern struct protocol proto_quic6;
 
 extern struct quic_dghdlr *quic_dghdlrs;
 
+extern THREAD_LOCAL struct cshared quic_mem_diff;
+
 #endif /* _HAPROXY_PROTO_QUIC_H  */
diff --git a/include/haproxy/quic_cc.h b/include/haproxy/quic_cc.h
index 6569799ff..4360a5af0 100644
--- a/include/haproxy/quic_cc.h
+++ b/include/haproxy/quic_cc.h
@@ -29,9 +29,11 @@
 #include <haproxy/api.h>
 #include <haproxy/buf.h>
 #include <haproxy/chunk.h>
+#include <haproxy/proto_quic.h>
 #include <haproxy/quic_cc-t.h>
 #include <haproxy/quic_conn-t.h>
 #include <haproxy/quic_loss.h>
+#include <haproxy/thread.h>
 
 void quic_cc_init(struct quic_cc *cc, struct quic_cc_algo *algo, struct quic_conn *qc);
 void quic_cc_event(struct quic_cc *cc, struct quic_cc_event *ev);
@@ -91,6 +93,7 @@ static inline void quic_cc_path_init(struct quic_cc_path *path, int ipv4, unsign
 	*(size_t *)&path->mtu = max_dgram_sz;
 	path->initial_wnd = QUIC_MIN(10 * max_dgram_sz, QUIC_MAX(max_dgram_sz << 1, 14720U));
 	path->cwnd = path->initial_wnd;
+	cshared_add(&quic_mem_diff, path->cwnd);
 	path->cwnd_last_max = path->cwnd;
 	path->limit_max = max_cwnd;
 	path->limit_min = max_dgram_sz << 1;
diff --git a/src/proto_quic.c b/src/proto_quic.c
index a0e9812c7..7dfe5fd32 100644
--- a/src/proto_quic.c
+++ b/src/proto_quic.c
@@ -48,11 +48,15 @@
 #include <haproxy/sock.h>
 #include <haproxy/sock_inet.h>
 #include <haproxy/task.h>
+#include <haproxy/thread.h>
 #include <haproxy/tools.h>
 
 /* per-thread quic datagram handlers */
 struct quic_dghdlr *quic_dghdlrs;
 
+static uint64_t quic_mem_global;
+THREAD_LOCAL struct cshared quic_mem_diff;
+
 /* Size of the internal buffer of QUIC RX buffer at the fd level */
 #define QUIC_RX_BUFSZ  (1UL << 18)
 
@@ -659,6 +663,14 @@ static void quic_bind_tid_reset(struct connection *conn)
 	qc_bind_tid_reset(qc);
 }
 
+static int quic_init_mem(void)
+{
+	/* 1024 is enough to limit modification on global counter but keeping it precise enough even with a lot of threads */
+	cshared_init(&quic_mem_diff, &quic_mem_global, 1024);
+	return 1;
+}
+REGISTER_PER_THREAD_INIT(quic_init_mem);
+
 static int quic_alloc_dghdlrs(void)
 {
 	int i;
diff --git a/src/quic_cc.c b/src/quic_cc.c
index 0d9151ebb..31bb6e797 100644
--- a/src/quic_cc.c
+++ b/src/quic_cc.c
@@ -20,8 +20,10 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#include <haproxy/proto_quic.h>
 #include <haproxy/quic_cc.h>
 #include <haproxy/quic_pacing.h>
+#include <haproxy/thread.h>
 
 struct quic_cc_algo *default_quic_cc_algo = &quic_cc_algo_cubic;
 
@@ -79,14 +81,19 @@ static int quic_cwnd_may_increase(const struct quic_cc_path *path)
 /* Restore congestion window for <path> to its minimal value. */
 void quic_cc_path_reset(struct quic_cc_path *path)
 {
+	const uint64_t old = path->cwnd;
 	path->cwnd = path->limit_min;
+	cshared_add(&quic_mem_diff, path->cwnd - old);
 }
 
 /* Set congestion window for <path> to <val>. Min and max limits are enforced. */
 void quic_cc_path_set(struct quic_cc_path *path, uint64_t val)
 {
+	const uint64_t old = path->cwnd;
+
 	path->cwnd = QUIC_MIN(val, path->limit_max);
 	path->cwnd = QUIC_MAX(path->cwnd, path->limit_min);
+	cshared_add(&quic_mem_diff, path->cwnd - old);
 
 	path->cwnd_last_max = QUIC_MAX(path->cwnd, path->cwnd_last_max);
 }
@@ -97,9 +104,12 @@ void quic_cc_path_set(struct quic_cc_path *path, uint64_t val)
  */
 void quic_cc_path_inc(struct quic_cc_path *path, uint64_t val)
 {
+	const uint64_t old = path->cwnd;
+
 	if (quic_cwnd_may_increase(path)) {
 		path->cwnd = QUIC_MIN(path->cwnd + val, path->limit_max);
 		path->cwnd = QUIC_MAX(path->cwnd, path->limit_min);
+		cshared_add(&quic_mem_diff, path->cwnd - old);
 
 		path->cwnd_last_max = QUIC_MAX(path->cwnd, path->cwnd_last_max);
 	}
diff --git a/src/quic_conn.c b/src/quic_conn.c
index 547c89817..51ace545f 100644
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -1442,6 +1442,10 @@ void quic_conn_release(struct quic_conn *qc)
 		HA_ATOMIC_DEC(&qc->li->rx.quic_curr_accept);
 	}
 
+	/* Substract last congestion window from global memory counter. */
+	cshared_add(&quic_mem_diff, -qc->path->cwnd);
+	qc->path->cwnd = 0;
+
 	/* free remaining stream descriptors */
 	node = eb64_first(&qc->streams_by_id);
 	while (node) {