diff -Nru cups-1.1.23.orig/pdftops/Stream.cxx cups-1.1.23/pdftops/Stream.cxx
--- cups-1.1.23.orig/pdftops/Stream.cxx	2005-12-14 18:14:18.000000000 +0100
+++ cups-1.1.23/pdftops/Stream.cxx	2005-12-14 18:20:31.000000000 +0100
@@ -15,6 +15,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stddef.h>
+#include <limits.h>
 #ifndef WIN32
 #include <unistd.h>
 #endif
@@ -404,18 +405,41 @@
 
 StreamPredictor::StreamPredictor(Stream *strA, int predictorA,
 				 int widthA, int nCompsA, int nBitsA) {
+  int totalBits;
+
   str = strA;
   predictor = predictorA;
   width = widthA;
   nComps = nCompsA;
   nBits = nBitsA;
+  predLine = NULL;
+  ok = gFalse;
 
+  if (width <= 0 || nComps <= 0 || nBits <= 0 ||
+      nComps >= INT_MAX/nBits ||
+      width >= INT_MAX/nComps/nBits) {
+    return;
+  }
   nVals = width * nComps;
+  if (nVals + 7 <= 0) {
+    return;
+  }
+  totalBits = nVals * nBits;
+  if (totalBits == 0 ||
+      (totalBits / nBits) / nComps != width ||
+      totalBits + 7 < 0) {
+    return;
+  }
   pixBytes = (nComps * nBits + 7) >> 3;
-  rowBytes = ((nVals * nBits + 7) >> 3) + pixBytes;
+  rowBytes = ((totalBits + 7) >> 3) + pixBytes;
+  if (rowBytes < 0) {
+    return;
+  }
   predLine = (Guchar *)gmalloc(rowBytes);
   memset(predLine, 0, rowBytes);
   predIdx = rowBytes;
+
+  ok = gTrue;
 }
 
 StreamPredictor::~StreamPredictor() {
@@ -991,6 +1015,10 @@
     FilterStream(strA) {
   if (predictor != 1) {
     pred = new StreamPredictor(this, predictor, columns, colors, bits);
+    if (!pred->isOk()) {
+      delete pred;
+      pred = NULL;
+    }
   } else {
     pred = NULL;
   }
@@ -2891,6 +2919,10 @@
   height = read16();
   width = read16();
   numComps = str->getChar();
+  if (numComps <= 0 || numComps > 4) {
+    error(getPos(), "Bad number of components in DCT stream", prec);
+    return gFalse;
+  }
   if (prec != 8) {
     error(getPos(), "Bad DCT precision %d", prec);
     return gFalse;
@@ -2917,6 +2949,10 @@
   height = read16();
   width = read16();
   numComps = str->getChar();
+  if (numComps <= 0 || numComps > 4) {
+    error(getPos(), "Bad number of components in DCT stream");
+    return gFalse;
+  }
   if (prec != 8) {
     error(getPos(), "Bad DCT precision %d", prec);
     return gFalse;
@@ -2939,6 +2975,10 @@
 
   length = read16() - 2;
   scanInfo.numComps = str->getChar();
+  if (scanInfo.numComps <= 0 || scanInfo.numComps > 4) {
+    error(getPos(), "Bad number of components in DCT stream");
+    return gFalse;
+  }
   --length;
   if (length != 2 * scanInfo.numComps + 3) {
     error(getPos(), "Bad DCT scan info block");
@@ -3249,6 +3289,10 @@
     FilterStream(strA) {
   if (predictor != 1) {
     pred = new StreamPredictor(this, predictor, columns, colors, bits);
+    if (!pred->isOk()) {
+      delete pred;
+      pred = NULL;
+    }
   } else {
     pred = NULL;
   }
diff -Nru cups-1.1.23.orig/pdftops/Stream.h cups-1.1.23/pdftops/Stream.h
--- cups-1.1.23.orig/pdftops/Stream.h	2005-12-14 18:14:18.000000000 +0100
+++ cups-1.1.23/pdftops/Stream.h	2005-12-14 18:20:31.000000000 +0100
@@ -231,6 +231,8 @@
 
   ~StreamPredictor();
 
+  GBool isOk() { return ok; }
+
   int lookChar();
   int getChar();
 
@@ -248,6 +250,7 @@
   int rowBytes;			// bytes per line
   Guchar *predLine;		// line buffer
   int predIdx;			// current index in predLine
+  GBool ok;
 };
 
 //------------------------------------------------------------------------