diff --git a/src/creds/creds.c b/src/creds/creds.c
index c9d1a6e8d9..bbc705c006 100644
--- a/src/creds/creds.c
+++ b/src/creds/creds.c
@@ -996,8 +996,6 @@ static int vl_method_encrypt(Varlink *link, JsonVariant *parameters, VarlinkMeth
 
         assert(link);
 
-        json_variant_sensitive(parameters);
-
         r = varlink_dispatch(link, parameters, dispatch_table, &p);
         if (r != 0)
                 return r;
@@ -1079,9 +1077,6 @@ static int vl_method_decrypt(Varlink *link, JsonVariant *parameters, VarlinkMeth
 
         assert(link);
 
-        /* Let's also mark the (theoretically encrypted) input as sensitive, in case the NULL encryption scheme was used. */
-        json_variant_sensitive(parameters);
-
         r = varlink_dispatch(link, parameters, dispatch_table, &p);
         if (r != 0)
                 return r;
@@ -1144,7 +1139,7 @@ static int run(int argc, char *argv[]) {
 
                 /* Invocation as Varlink service */
 
-                r = varlink_server_new(&varlink_server, VARLINK_SERVER_ACCOUNT_UID|VARLINK_SERVER_INHERIT_USERDATA);
+                r = varlink_server_new(&varlink_server, VARLINK_SERVER_ACCOUNT_UID|VARLINK_SERVER_INHERIT_USERDATA|VARLINK_SERVER_INPUT_SENSITIVE);
                 if (r < 0)
                         return log_error_errno(r, "Failed to allocate Varlink server: %m");
 
diff --git a/src/home/homed-manager.c b/src/home/homed-manager.c
index 94b2ea5181..b1d0c51120 100644
--- a/src/home/homed-manager.c
+++ b/src/home/homed-manager.c
@@ -998,7 +998,7 @@ static int manager_bind_varlink(Manager *m) {
         assert(m);
         assert(!m->varlink_server);
 
-        r = varlink_server_new(&m->varlink_server, VARLINK_SERVER_ACCOUNT_UID|VARLINK_SERVER_INHERIT_USERDATA);
+        r = varlink_server_new(&m->varlink_server, VARLINK_SERVER_ACCOUNT_UID|VARLINK_SERVER_INHERIT_USERDATA|VARLINK_SERVER_INPUT_SENSITIVE);
         if (r < 0)
                 return log_error_errno(r, "Failed to allocate varlink server object: %m");
 
diff --git a/src/shared/varlink.c b/src/shared/varlink.c
index 699d21745f..96dfd8de92 100644
--- a/src/shared/varlink.c
+++ b/src/shared/varlink.c
@@ -184,6 +184,7 @@ struct Varlink {
         bool allow_fd_passing_output:1;
 
         bool output_buffer_sensitive:1; /* whether to erase the output buffer after writing it to the socket */
+        bool input_sensitive:1; /* Whether incoming messages might be sensitive */
 
         int af; /* address family if socket; AF_UNSPEC if not socket; negative if not known */
 
@@ -703,7 +704,7 @@ static void varlink_clear(Varlink *v) {
 
         varlink_clear_current(v);
 
-        v->input_buffer = mfree(v->input_buffer);
+        v->input_buffer = v->input_sensitive ? erase_and_free(v->input_buffer) : mfree(v->input_buffer);
         v->output_buffer = v->output_buffer_sensitive ? erase_and_free(v->output_buffer) : mfree(v->output_buffer);
 
         v->input_control_buffer = mfree(v->input_control_buffer);
@@ -1022,7 +1023,8 @@ static int varlink_read(Varlink *v) {
 }
 
 static int varlink_parse_message(Varlink *v) {
-        const char *e, *begin;
+        const char *e;
+        char *begin;
         size_t sz;
         int r;
 
@@ -1047,6 +1049,8 @@ static int varlink_parse_message(Varlink *v) {
         sz = e - begin + 1;
 
         r = json_parse(begin, 0, &v->current, NULL, NULL);
+        if (v->input_sensitive)
+                explicit_bzero_safe(begin, sz);
         if (r < 0) {
                 /* If we encounter a parse failure flush all data. We cannot possibly recover from this,
                  * hence drop all buffered data now. */
@@ -1054,6 +1058,13 @@ static int varlink_parse_message(Varlink *v) {
                 return varlink_log_errno(v, r, "Failed to parse JSON: %m");
         }
 
+        if (v->input_sensitive) {
+                /* Mark the parameters subfield as sensitive right-away, if that's requested */
+                JsonVariant *parameters = json_variant_by_key(v->current, "parameters");
+                if (parameters)
+                        json_variant_sensitive(parameters);
+        }
+
         v->input_buffer_size -= sz;
 
         if (v->input_buffer_size == 0)
@@ -3097,6 +3108,13 @@ int varlink_set_allow_fd_passing_output(Varlink *v, bool b) {
         return 0;
 }
 
+int varlink_set_input_sensitive(Varlink *v) {
+        assert_return(v, -EINVAL);
+
+        v->input_sensitive = true;
+        return 0;
+}
+
 int varlink_server_new(VarlinkServer **ret, VarlinkServerFlags flags) {
         _cleanup_(varlink_server_unrefp) VarlinkServer *s = NULL;
         int r;
@@ -3325,6 +3343,9 @@ static int connect_callback(sd_event_source *source, int fd, uint32_t revents, v
 
         TAKE_FD(cfd);
 
+        if (FLAGS_SET(ss->server->flags, VARLINK_SERVER_INPUT_SENSITIVE))
+                varlink_set_input_sensitive(v);
+
         if (ss->server->connect_callback) {
                 r = ss->server->connect_callback(ss->server, v, ss->server->userdata);
                 if (r < 0) {
diff --git a/src/shared/varlink.h b/src/shared/varlink.h
index a971762a51..418ba49d1a 100644
--- a/src/shared/varlink.h
+++ b/src/shared/varlink.h
@@ -47,7 +47,8 @@ typedef enum VarlinkServerFlags {
         VARLINK_SERVER_MYSELF_ONLY      = 1 << 1, /* Only accessible by our own UID */
         VARLINK_SERVER_ACCOUNT_UID      = 1 << 2, /* Do per user accounting */
         VARLINK_SERVER_INHERIT_USERDATA = 1 << 3, /* Initialize Varlink connection userdata from VarlinkServer userdata */
-        _VARLINK_SERVER_FLAGS_ALL = (1 << 4) - 1,
+        VARLINK_SERVER_INPUT_SENSITIVE  = 1 << 4, /* Automatically mark al connection input as sensitive */
+        _VARLINK_SERVER_FLAGS_ALL = (1 << 5) - 1,
 } VarlinkServerFlags;
 
 typedef int (*VarlinkMethod)(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata);
@@ -154,6 +155,9 @@ VarlinkServer* varlink_get_server(Varlink *v);
 
 int varlink_set_description(Varlink *v, const char *d);
 
+/* Automatically mark the parameters part of incoming messages as security sensitive */
+int varlink_set_input_sensitive(Varlink *v);
+
 /* Create a varlink server */
 int varlink_server_new(VarlinkServer **ret, VarlinkServerFlags flags);
 VarlinkServer *varlink_server_ref(VarlinkServer *s);