diff --git a/deps/nghttp2/lib/Makefile.in b/deps/nghttp2/lib/Makefile.in
index 14686ef14b1..7a4cb5e9740 100644
--- a/deps/nghttp2/lib/Makefile.in
+++ b/deps/nghttp2/lib/Makefile.in
@@ -360,6 +360,8 @@ LIBNGHTTP3_LIBS = @LIBNGHTTP3_LIBS@
 LIBNGTCP2_CFLAGS = @LIBNGTCP2_CFLAGS@
 LIBNGTCP2_CRYPTO_BORINGSSL_CFLAGS = @LIBNGTCP2_CRYPTO_BORINGSSL_CFLAGS@
 LIBNGTCP2_CRYPTO_BORINGSSL_LIBS = @LIBNGTCP2_CRYPTO_BORINGSSL_LIBS@
+LIBNGTCP2_CRYPTO_OSSL_CFLAGS = @LIBNGTCP2_CRYPTO_OSSL_CFLAGS@
+LIBNGTCP2_CRYPTO_OSSL_LIBS = @LIBNGTCP2_CRYPTO_OSSL_LIBS@
 LIBNGTCP2_CRYPTO_QUICTLS_CFLAGS = @LIBNGTCP2_CRYPTO_QUICTLS_CFLAGS@
 LIBNGTCP2_CRYPTO_QUICTLS_LIBS = @LIBNGTCP2_CRYPTO_QUICTLS_LIBS@
 LIBNGTCP2_CRYPTO_WOLFSSL_CFLAGS = @LIBNGTCP2_CRYPTO_WOLFSSL_CFLAGS@
diff --git a/deps/nghttp2/lib/includes/Makefile.in b/deps/nghttp2/lib/includes/Makefile.in
index 778dcb874c9..7504f8e7c75 100644
--- a/deps/nghttp2/lib/includes/Makefile.in
+++ b/deps/nghttp2/lib/includes/Makefile.in
@@ -265,6 +265,8 @@ LIBNGHTTP3_LIBS = @LIBNGHTTP3_LIBS@
 LIBNGTCP2_CFLAGS = @LIBNGTCP2_CFLAGS@
 LIBNGTCP2_CRYPTO_BORINGSSL_CFLAGS = @LIBNGTCP2_CRYPTO_BORINGSSL_CFLAGS@
 LIBNGTCP2_CRYPTO_BORINGSSL_LIBS = @LIBNGTCP2_CRYPTO_BORINGSSL_LIBS@
+LIBNGTCP2_CRYPTO_OSSL_CFLAGS = @LIBNGTCP2_CRYPTO_OSSL_CFLAGS@
+LIBNGTCP2_CRYPTO_OSSL_LIBS = @LIBNGTCP2_CRYPTO_OSSL_LIBS@
 LIBNGTCP2_CRYPTO_QUICTLS_CFLAGS = @LIBNGTCP2_CRYPTO_QUICTLS_CFLAGS@
 LIBNGTCP2_CRYPTO_QUICTLS_LIBS = @LIBNGTCP2_CRYPTO_QUICTLS_LIBS@
 LIBNGTCP2_CRYPTO_WOLFSSL_CFLAGS = @LIBNGTCP2_CRYPTO_WOLFSSL_CFLAGS@
diff --git a/deps/nghttp2/lib/includes/nghttp2/nghttp2ver.h b/deps/nghttp2/lib/includes/nghttp2/nghttp2ver.h
index 1302eb57bc5..776c4924276 100644
--- a/deps/nghttp2/lib/includes/nghttp2/nghttp2ver.h
+++ b/deps/nghttp2/lib/includes/nghttp2/nghttp2ver.h
@@ -29,7 +29,7 @@
  * @macro
  * Version number of the nghttp2 library release
  */
-#define NGHTTP2_VERSION "1.65.0"
+#define NGHTTP2_VERSION "1.66.0"
 
 /**
  * @macro
@@ -37,6 +37,6 @@
  * release. This is a 24 bit number with 8 bits for major number, 8 bits
  * for minor and 8 bits for patch. Version 1.2.3 becomes 0x010203.
  */
-#define NGHTTP2_VERSION_NUM 0x014100
+#define NGHTTP2_VERSION_NUM 0x014200
 
 #endif /* NGHTTP2VER_H */
diff --git a/deps/nghttp2/lib/nghttp2_session.c b/deps/nghttp2/lib/nghttp2_session.c
index f5bda333f83..dc1a00cf576 100644
--- a/deps/nghttp2/lib/nghttp2_session.c
+++ b/deps/nghttp2/lib/nghttp2_session.c
@@ -41,7 +41,7 @@
 #include "nghttp2_debug.h"
 #include "nghttp2_submit.h"
 
-nghttp2_stream root;
+nghttp2_stream nghttp2_stream_root;
 
 /*
  * Returns non-zero if the number of outgoing opened streams is larger
@@ -1092,6 +1092,15 @@ int nghttp2_session_add_item(nghttp2_session *session,
 
 int nghttp2_session_add_rst_stream(nghttp2_session *session, int32_t stream_id,
                                    uint32_t error_code) {
+  return nghttp2_session_add_rst_stream_continue(
+    session, stream_id, error_code,
+    /* continue_without_stream = */ 1);
+}
+
+int nghttp2_session_add_rst_stream_continue(nghttp2_session *session,
+                                            int32_t stream_id,
+                                            uint32_t error_code,
+                                            int continue_without_stream) {
   int rv;
   nghttp2_outbound_item *item;
   nghttp2_frame *frame;
@@ -1148,6 +1157,12 @@ int nghttp2_session_add_rst_stream(nghttp2_session *session, int32_t stream_id,
     }
   }
 
+  /* To keep the old behaviour, do not fail if stream was not
+     found. */
+  if (!continue_without_stream && !stream) {
+    return 0;
+  }
+
   item = nghttp2_mem_malloc(mem, sizeof(nghttp2_outbound_item));
   if (item == NULL) {
     return NGHTTP2_ERR_NOMEM;
@@ -7715,7 +7730,7 @@ int32_t nghttp2_session_get_last_proc_stream_id(nghttp2_session *session) {
 nghttp2_stream *nghttp2_session_find_stream(nghttp2_session *session,
                                             int32_t stream_id) {
   if (stream_id == 0) {
-    return &root;
+    return &nghttp2_stream_root;
   }
 
   return nghttp2_session_get_stream_raw(session, stream_id);
@@ -7724,7 +7739,7 @@ nghttp2_stream *nghttp2_session_find_stream(nghttp2_session *session,
 nghttp2_stream *nghttp2_session_get_root_stream(nghttp2_session *session) {
   (void)session;
 
-  return &root;
+  return &nghttp2_stream_root;
 }
 
 int nghttp2_session_check_server_session(nghttp2_session *session) {
diff --git a/deps/nghttp2/lib/nghttp2_session.h b/deps/nghttp2/lib/nghttp2_session.h
index 6a54d35fcab..419d23b5a96 100644
--- a/deps/nghttp2/lib/nghttp2_session.h
+++ b/deps/nghttp2/lib/nghttp2_session.h
@@ -45,7 +45,7 @@
    preface handling. */
 extern int nghttp2_enable_strict_preface;
 
-extern nghttp2_stream root;
+extern nghttp2_stream nghttp2_stream_root;
 
 /*
  * Option flags.
@@ -402,6 +402,13 @@ int nghttp2_session_is_my_stream_id(nghttp2_session *session,
 int nghttp2_session_add_item(nghttp2_session *session,
                              nghttp2_outbound_item *item);
 
+/*
+ * This function wraps around nghttp2_session_add_rst_stream_continue
+ * with continue_without_stream = 1.
+ */
+int nghttp2_session_add_rst_stream(nghttp2_session *session, int32_t stream_id,
+                                   uint32_t error_code);
+
 /*
  * Adds RST_STREAM frame for the stream |stream_id| with the error
  * code |error_code|. This is a convenient function built on top of
@@ -409,7 +416,9 @@ int nghttp2_session_add_item(nghttp2_session *session,
  *
  * This function simply returns 0 without adding RST_STREAM frame if
  * given stream is in NGHTTP2_STREAM_CLOSING state, because multiple
- * RST_STREAM for a stream is redundant.
+ * RST_STREAM for a stream is redundant.  It also returns 0 without
+ * adding the frame if |continue_without_stream| is nonzero, and
+ * stream was already gone.
  *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
@@ -417,8 +426,10 @@ int nghttp2_session_add_item(nghttp2_session *session,
  * NGHTTP2_ERR_NOMEM
  *     Out of memory.
  */
-int nghttp2_session_add_rst_stream(nghttp2_session *session, int32_t stream_id,
-                                   uint32_t error_code);
+int nghttp2_session_add_rst_stream_continue(nghttp2_session *session,
+                                            int32_t stream_id,
+                                            uint32_t error_code,
+                                            int continue_without_stream);
 
 /*
  * Adds PING frame. This is a convenient function built on top of
diff --git a/deps/nghttp2/lib/nghttp2_stream.c b/deps/nghttp2/lib/nghttp2_stream.c
index afbd7c2d9e0..0f2d3658775 100644
--- a/deps/nghttp2/lib/nghttp2_stream.c
+++ b/deps/nghttp2/lib/nghttp2_stream.c
@@ -151,7 +151,7 @@ void nghttp2_stream_promise_fulfilled(nghttp2_stream *stream) {
 }
 
 nghttp2_stream_proto_state nghttp2_stream_get_state(nghttp2_stream *stream) {
-  if (stream == &root) {
+  if (stream == &nghttp2_stream_root) {
     return NGHTTP2_STREAM_STATE_IDLE;
   }
 
diff --git a/deps/nghttp2/lib/nghttp2_submit.c b/deps/nghttp2/lib/nghttp2_submit.c
index d481aebde22..5c6390fa759 100644
--- a/deps/nghttp2/lib/nghttp2_submit.c
+++ b/deps/nghttp2/lib/nghttp2_submit.c
@@ -185,7 +185,8 @@ int nghttp2_submit_rst_stream(nghttp2_session *session, uint8_t flags,
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
 
-  return nghttp2_session_add_rst_stream(session, stream_id, error_code);
+  return nghttp2_session_add_rst_stream_continue(
+    session, stream_id, error_code, /* continue_without_stream = */ 0);
 }
 
 int nghttp2_submit_goaway(nghttp2_session *session, uint8_t flags,