https://github.com/ImageMagick/ImageMagick/issues/724

diff --git a/coders/pdf.c b/coders/pdf.c
index 40a723c847e46b17c0c4da05de25f0f6d5b3dba9..09bb4aed4d3b1d0fab455f4d7ac96be0d7c9d9fa 100644 (file)
--- a/coders/pdf.c
+++ b/coders/pdf.c
@@ -145,6 +145,8 @@ static int MagickDLLCall PDFDelegateMessage(void *handle,const char *message,
       *messages=(char *) ResizeQuantumMemory(*messages,offset+length+1,
         sizeof(char *));
     }
+  if (*messages == (char *) NULL)
+    return(0);
   (void) memcpy(*messages+offset,message,length);
   (*messages)[length+offset] ='\0';
   return(length);