diff --git a/common/rfb/CMsgReader.cxx b/common/rfb/CMsgReader.cxx
index 86288ad..a9e12d7 100644
--- a/common/rfb/CMsgReader.cxx
+++ b/common/rfb/CMsgReader.cxx
@@ -1,5 +1,5 @@
 /* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
- * Copyright 2009-2017 Pierre Ossman for Cendio AB
+ * Copyright 2009-2019 Pierre Ossman for Cendio AB
  * 
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,8 +20,11 @@
 #include <assert.h>
 #include <stdio.h>
 
-#include <rfb/msgTypes.h>
 #include <rdr/InStream.h>
+#include <rdr/ZlibInStream.h>
+
+#include <rfb/msgTypes.h>
+#include <rfb/clipboardTypes.h>
 #include <rfb/Exception.h>
 #include <rfb/LogWriter.h>
 #include <rfb/util.h>
@@ -30,6 +33,8 @@
 
 static rfb::LogWriter vlog("CMsgReader");
 
+static rfb::IntParameter maxCutText("MaxCutText", "Maximum permitted length of an incoming clipboard update", 256*1024);
+
 using namespace rfb;
 
 CMsgReader::CMsgReader(CMsgHandler* handler_, rdr::InStream* is_)
@@ -152,7 +157,15 @@
 {
   is->skip(3);
   rdr::U32 len = is->readU32();
-  if (len > 256*1024) {
+
+  if (len & 0x80000000) {
+    rdr::S32 slen = len;
+    slen = -slen;
+    readExtendedClipboard(slen);
+    return;
+  }
+
+  if (len > (size_t)maxCutText) {
     is->skip(len);
     vlog.error("cut text too long (%d bytes) - ignoring",len);
     return;
@@ -163,6 +176,99 @@
   handler->serverCutText(filtered.buf);
 }
 
+void CMsgReader::readExtendedClipboard(rdr::S32 len)
+{
+  rdr::U32 flags;
+  rdr::U32 action;
+
+  if (len < 4)
+    throw Exception("Invalid extended clipboard message");
+  if (len > maxCutText) {
+    vlog.error("Extended clipboard message too long (%d bytes) - ignoring", len);
+    is->skip(len);
+    return;
+  }
+
+  flags = is->readU32();
+  action = flags & clipboardActionMask;
+
+  if (action & clipboardCaps) {
+    int i;
+    size_t num;
+    rdr::U32 lengths[16];
+
+    num = 0;
+    for (i = 0;i < 16;i++) {
+      if (flags & (1 << i))
+        num++;
+    }
+
+    if (len < (rdr::S32)(4 + 4*num))
+      throw Exception("Invalid extended clipboard message");
+
+    num = 0;
+    for (i = 0;i < 16;i++) {
+      if (flags & (1 << i))
+        lengths[num++] = is->readU32();
+    }
+
+    handler->handleClipboardCaps(flags, lengths);
+  } else if (action == clipboardProvide) {
+    rdr::ZlibInStream zis;
+
+    int i;
+    size_t num;
+    size_t lengths[16];
+    rdr::U8* buffers[16];
+
+    zis.setUnderlying(is, len - 4);
+
+    num = 0;
+    for (i = 0;i < 16;i++) {
+      if (!(flags & 1 << i))
+        continue;
+
+      lengths[num] = zis.readU32();
+      if (lengths[num] > (size_t)maxCutText) {
+        vlog.error("Extended clipboard data too long (%d bytes) - ignoring",
+                   (unsigned)lengths[num]);
+        zis.skip(lengths[num]);
+        flags &= ~(1 << i);
+        continue;
+      }
+
+      buffers[num] = new rdr::U8[lengths[num]];
+      zis.readBytes(buffers[num], lengths[num]);
+      num++;
+    }
+
+    zis.removeUnderlying();
+
+    handler->handleClipboardProvide(flags, lengths, buffers);
+
+    num = 0;
+    for (i = 0;i < 16;i++) {
+      if (!(flags & 1 << i))
+        continue;
+      delete [] buffers[num++];
+    }
+  } else {
+    switch (action) {
+    case clipboardRequest:
+      handler->handleClipboardRequest(flags);
+      break;
+    case clipboardPeek:
+      handler->handleClipboardPeek(flags);
+      break;
+    case clipboardNotify:
+      handler->handleClipboardNotify(flags);
+      break;
+    default:
+      throw Exception("Invalid extended clipboard action");
+    }
+  }
+}
+
 void CMsgReader::readFence()
 {
   rdr::U32 flags;