--- tiff-3.8.2/libtiff/tif_lzw.c	
+++ tiff-3.8.2/libtiff/tif_lzw.c	
@@ -237,6 +237,12 @@ LZWSetupDecode(TIFF* tif)
                     sp->dec_codetab[code].length = 1;
                     sp->dec_codetab[code].next = NULL;
                 } while (code--);
+		/*
+		* Zero-out the unused entries
+		*/
+		_TIFFmemset(&sp->dec_codetab[CODE_CLEAR], 0,
+		(CODE_FIRST-CODE_CLEAR)*sizeof (code_t));
+
 	}
 	return (1);
 }
@@ -415,6 +421,12 @@ LZWDecode(TIFF* tif, tidata_t op0, tsize
 			NextCode(tif, sp, bp, code, GetNextCode);
 			if (code == CODE_EOI)
 				break;
+			if (code == CODE_CLEAR) {
+				TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+				"LZWDecode: Corrupted LZW table at scanline %d",
+				tif->tif_row);
+				return (0);
+			}
 			*op++ = (char)code, occ--;
 			oldcodep = sp->dec_codetab + code;
 			continue;
@@ -612,6 +624,12 @@ LZWDecodeCompat(TIFF* tif, tidata_t op0,
 			NextCode(tif, sp, bp, code, GetNextCodeCompat);
 			if (code == CODE_EOI)
 				break;
+			if (code == CODE_CLEAR) {
+				TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+				"LZWDecode: Corrupted LZW table at scanline %d",
+				tif->tif_row);
+				return (0);
+			}
 			*op++ = code, occ--;
 			oldcodep = sp->dec_codetab + code;
 			continue;