diff --git a/core/rfb.js b/core/rfb.js
index 80011e4a10203806f14df1ffc3b8425861a965a7..b8b75557417cfb0f0522c0abbb56ec23b63d625b 100644
--- a/core/rfb.js
+++ b/core/rfb.js
@@ -2429,11 +2429,9 @@ export default class RFB extends EventTargetMixin {
                 }
 
             } else if (actions === extendedClipboardActionProvide) {
-                if (this._viewOnly) {
-                    return true;
-                }
-
-                if (!(formats & extendedClipboardFormatText)) {
+                if (this._viewOnly || !(formats & extendedClipboardFormatText)) {
+                    // Ignored clipboard bytes must not become the next RFB message.
+                    this._sock.rQskipBytes(length - 4);
                     return true;
                 }
                 // Ignore what we had in our clipboard client side.