diff --git a/ui/vnc-enc-tight.c b/ui/vnc-enc-tight.c
index b8581dd2e9..49df85e763 100644
--- a/ui/vnc-enc-tight.c
+++ b/ui/vnc-enc-tight.c
@@ -461,9 +461,10 @@ static int tight_fill_palette(VncState *vs, int x, int y,
                                                                         \
         src = (uint##bpp##_t *) buf;                                    \
                                                                         \
-        for (i = 0; i < count; i++) {                                   \
+        for (i = 0; i < count; ) {                                      \
                                                                         \
             rgb = *src++;                                               \
+            i++;                                                        \
             rep = 0;                                                    \
             while (i < count && *src == rgb) {                          \
                 rep++, src++, i++;                                      \
@@ -1457,11 +1458,17 @@ static int send_sub_rect_jpeg(VncState *vs, int x, int y, int w, int h,
 }
 #endif
 
-static __thread VncPalette color_count_palette;
+static __thread VncPalette *color_count_palette;
+static __thread Notifier vnc_tight_cleanup_notifier;
+
+static void vnc_tight_cleanup(Notifier *n, void *value)
+{
+    g_free(color_count_palette);
+    color_count_palette = NULL;
+}
 
 static int send_sub_rect(VncState *vs, int x, int y, int w, int h)
 {
-    VncPalette *palette = &color_count_palette;
     uint32_t bg = 0, fg = 0;
     int colors;
     int ret = 0;
@@ -1470,6 +1477,12 @@ static int send_sub_rect(VncState *vs, int x, int y, int w, int h)
     bool allow_jpeg = true;
 #endif
 
+    if (!color_count_palette) {
+        color_count_palette = g_malloc(sizeof(VncPalette));
+        vnc_tight_cleanup_notifier.notify = vnc_tight_cleanup;
+        qemu_thread_atexit_add(&vnc_tight_cleanup_notifier);
+    }
+
     vnc_framebuffer_update(vs, x, y, w, h, vs->tight.type);
 
     vnc_tight_start(vs);
@@ -1490,17 +1503,19 @@ static int send_sub_rect(VncState *vs, int x, int y, int w, int h)
     }
 #endif
 
-    colors = tight_fill_palette(vs, x, y, w * h, &bg, &fg, palette);
+    colors = tight_fill_palette(vs, x, y, w * h, &bg, &fg, color_count_palette);
 
 #ifdef CONFIG_VNC_JPEG
     if (allow_jpeg && vs->tight.quality != (uint8_t)-1) {
-        ret = send_sub_rect_jpeg(vs, x, y, w, h, bg, fg, colors, palette,
-                                 force_jpeg);
+        ret = send_sub_rect_jpeg(vs, x, y, w, h, bg, fg, colors,
+                                 color_count_palette, force_jpeg);
     } else {
-        ret = send_sub_rect_nojpeg(vs, x, y, w, h, bg, fg, colors, palette);
+        ret = send_sub_rect_nojpeg(vs, x, y, w, h, bg, fg, colors,
+                                   color_count_palette);
     }
 #else
-    ret = send_sub_rect_nojpeg(vs, x, y, w, h, bg, fg, colors, palette);
+    ret = send_sub_rect_nojpeg(vs, x, y, w, h, bg, fg, colors,
+                               color_count_palette);
 #endif
 
     return ret;
diff --git a/ui/vnc.c b/ui/vnc.c
index e3f857cc90..3ce3a5beec 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -1024,6 +1024,11 @@ static int find_and_clear_dirty_height(VncState *vs,
 
 static int vnc_update_client(VncState *vs, int has_dirty, bool sync)
 {
+    if (vs->disconnecting) {
+        vnc_disconnect_finish(vs);
+        return 0;
+    }
+
     vs->has_dirty += has_dirty;
     if (vs->need_update && !vs->disconnecting) {
         VncDisplay *vd = vs->vd;