diff --git a/poppler/CairoOutputDev.cc b/poppler/CairoOutputDev.cc
index d8f78d7..2312514 100644
--- a/poppler/CairoOutputDev.cc
+++ b/poppler/CairoOutputDev.cc
@@ -1158,6 +1158,13 @@ void CairoOutputDev::beginString(GfxState *state, GooString *s)
   }
 }
 
+
+#define UNICODE_VALID(Char)                   \
+    ((Char) < 0x110000 &&                     \
+     (((Char) & 0xFFFFF800) != 0xD800) &&     \
+     ((Char) < 0xFDD0 || (Char) > 0xFDEF) &&  \
+     ((Char) & 0xFFFE) != 0xFFFE)
+                   
 void CairoOutputDev::drawChar(GfxState *state, double x, double y,
 			      double dx, double dy,
 			      double originX, double originY,
@@ -1179,7 +1186,13 @@ void CairoOutputDev::drawChar(GfxState *state, double x, double y,
       }
       clusters[clusterCount].num_bytes = 0;
       for (int i = 0; i < uLen; i++) {
-	int size = mapUTF8 (u[i], utf8 + utf8Count, utf8Max - utf8Count);
+        int size;
+        /* Replace the charcter with 0xfffe if it is not valid UTF-8. */
+        if (UNICODE_VALID(u[i]))
+          size = mapUTF8 (u[i], utf8 + utf8Count, utf8Max - utf8Count);
+        else
+          size = mapUTF8((Unicode)0xfffd, utf8 + utf8Count, utf8Max - utf8Count);
+          
 	utf8Count += size;
 	clusters[clusterCount].num_bytes += size;
       }