diff --git a/apps/emqx_auth_http/src/emqx_auth_http.app.src b/apps/emqx_auth_http/src/emqx_auth_http.app.src
index c5ad881d1..4f625140b 100644
--- a/apps/emqx_auth_http/src/emqx_auth_http.app.src
+++ b/apps/emqx_auth_http/src/emqx_auth_http.app.src
@@ -1,7 +1,7 @@
 %% -*- mode: erlang -*-
 {application, emqx_auth_http, [
     {description, "EMQX External HTTP API Authentication and Authorization"},
-    {vsn, "0.2.1"},
+    {vsn, "0.2.2"},
     {registered, []},
     {mod, {emqx_auth_http_app, []}},
     {applications, [
diff --git a/apps/emqx_auth_http/src/emqx_authz_http.erl b/apps/emqx_auth_http/src/emqx_authz_http.erl
index ffc339393..49296f690 100644
--- a/apps/emqx_auth_http/src/emqx_authz_http.erl
+++ b/apps/emqx_auth_http/src/emqx_authz_http.erl
@@ -38,6 +38,10 @@
 -compile(nowarn_export_all).
 -endif.
 
+-define(VAR_ACCESS, "access").
+-define(LEGACY_SUBSCRIBE_ACTION, 1).
+-define(LEGACY_PUBLISH_ACTION, 2).
+
 -define(ALLOWED_VARS, [
     ?VAR_USERNAME,
     ?VAR_CLIENTID,
@@ -48,6 +52,7 @@
     ?VAR_ACTION,
     ?VAR_CERT_SUBJECT,
     ?VAR_CERT_CN_NAME,
+    ?VAR_ACCESS,
     ?VAR_NS_CLIENT_ATTRS
 ]).
 
@@ -214,7 +219,7 @@ generate_request(
         _ ->
             NPath = append_query(Path, Query),
             NBody = serialize_body(
-                proplists:get_value(<<"accept">>, Headers, <<"application/json">>),
+                proplists:get_value(<<"content-type">>, Headers, <<"application/json">>),
                 Body
             ),
             {NPath, Headers, NBody}
@@ -248,7 +253,14 @@ serialize_body(<<"application/x-www-form-urlencoded">>, Body) ->
 
 client_vars(Client, Action, Topic) ->
     Vars = emqx_authz_utils:vars_for_rule_query(Client, Action),
-    Vars#{topic => Topic}.
+    add_legacy_access_var(Vars#{topic => Topic}).
+
+add_legacy_access_var(#{action := subscribe} = Vars) ->
+    Vars#{access => ?LEGACY_SUBSCRIBE_ACTION};
+add_legacy_access_var(#{action := publish} = Vars) ->
+    Vars#{access => ?LEGACY_PUBLISH_ACTION};
+add_legacy_access_var(Vars) ->
+    Vars.
 
 to_list(A) when is_atom(A) ->
     atom_to_list(A);
diff --git a/apps/emqx_auth_http/test/emqx_authz_http_SUITE.erl b/apps/emqx_auth_http/test/emqx_authz_http_SUITE.erl
index 70fda514f..93990791d 100644
--- a/apps/emqx_auth_http/test/emqx_authz_http_SUITE.erl
+++ b/apps/emqx_auth_http/test/emqx_authz_http_SUITE.erl
@@ -199,6 +199,7 @@ t_query_params(_Config) ->
                 mountpoint := <<"MOUNTPOINT">>,
                 topic := <<"t/1">>,
                 action := <<"publish">>,
+                access := <<"2">>,
                 qos := <<"1">>,
                 retain := <<"false">>
             } = cowboy_req:match_qs(
@@ -210,6 +211,7 @@ t_query_params(_Config) ->
                     mountpoint,
                     topic,
                     action,
+                    access,
                     qos,
                     retain
                 ],
@@ -227,6 +229,7 @@ t_query_params(_Config) ->
                 "mountpoint=${mountpoint}&"
                 "topic=${topic}&"
                 "action=${action}&"
+                "access=${access}&"
                 "qos=${qos}&"
                 "retain=${retain}"
             >>
@@ -261,6 +264,7 @@ t_path(_Config) ->
                     "MOUNTPOINT/"
                     "t%2F1/"
                     "publish/"
+                    "2/"
                     "1/"
                     "false"
                 >>,
@@ -278,6 +282,7 @@ t_path(_Config) ->
                 "${mountpoint}/"
                 "${topic}/"
                 "${action}/"
+                "${access}/"
                 "${qos}/"
                 "${retain}"
             >>
@@ -318,6 +323,7 @@ t_json_body(_Config) ->
                     <<"mountpoint">> := <<"MOUNTPOINT">>,
                     <<"topic">> := <<"t">>,
                     <<"action">> := <<"publish">>,
+                    <<"access">> := <<"2">>,
                     <<"qos">> := <<"1">>,
                     <<"retain">> := <<"false">>
                 },
@@ -335,6 +341,7 @@ t_json_body(_Config) ->
                 <<"mountpoint">> => <<"${mountpoint}">>,
                 <<"topic">> => <<"${topic}">>,
                 <<"action">> => <<"${action}">>,
+                <<"access">> => <<"${access}">>,
                 <<"qos">> => <<"${qos}">>,
                 <<"retain">> => <<"${retain}">>
             }
@@ -402,7 +409,7 @@ t_placeholder_and_body(_Config) ->
                 cowboy_req:path(Req0)
             ),
 
-            {ok, [{PostVars, true}], Req1} = cowboy_req:read_urlencoded_body(Req0),
+            {ok, PostVars, Req1} = cowboy_req:read_urlencoded_body(Req0),
 
             ?assertMatch(
                 #{
@@ -413,10 +420,11 @@ t_placeholder_and_body(_Config) ->
                     <<"mountpoint">> := <<"MOUNTPOINT">>,
                     <<"topic">> := <<"t">>,
                     <<"action">> := <<"publish">>,
+                    <<"access">> := <<"2">>,
                     <<"CN">> := ?PH_CERT_CN_NAME,
                     <<"CS">> := ?PH_CERT_SUBJECT
                 },
-                emqx_utils_json:decode(PostVars, [return_maps])
+                maps:from_list(PostVars)
             ),
             {ok, ?AUTHZ_HTTP_RESP(allow, Req1), State}
         end,
@@ -430,6 +438,7 @@ t_placeholder_and_body(_Config) ->
                 <<"mountpoint">> => <<"${mountpoint}">>,
                 <<"topic">> => <<"${topic}">>,
                 <<"action">> => <<"${action}">>,
+                <<"access">> => <<"${access}">>,
                 <<"CN">> => ?PH_CERT_CN_NAME,
                 <<"CS">> => ?PH_CERT_SUBJECT
             },
diff --git a/changes/ce/fix-13164.en.md b/changes/ce/fix-13164.en.md
new file mode 100644
index 000000000..c0ce937da
--- /dev/null
+++ b/changes/ce/fix-13164.en.md
@@ -0,0 +1,6 @@
+Fix HTTP authorization request body encoding.
+
+Prior to this fix, the HTTP authorization request body encoding format was taken from the `accept` header.
+The fix is to respect the `content-type` header instead.
+Also added `access` templating variable for v4 compatibility.
+The access code of SUBSCRIBE action is `1` and SUBSCRIBE action is `2`.