diff --git a/xpdf/JBIG2Stream.cc b/xpdf/JBIG2Stream.cc
index 8588931..00c8950 100644
--- a/xpdf/JBIG2Stream.cc
+++ b/xpdf/JBIG2Stream.cc
@@ -1977,7 +1977,14 @@ void JBIG2Stream::readTextRegionSeg(Guint segNum, GBool imm,
   for (i = 0; i < nRefSegs; ++i) {
     if ((seg = findSegment(refSegs[i]))) {
       if (seg->getType() == jbig2SegSymbolDict) {
-	numSyms += ((JBIG2SymbolDict *)seg)->getSize();
+	Guint segSize = ((JBIG2SymbolDict *)seg)->getSize();
+	if (segSize > INT_MAX || numSyms > INT_MAX - segSize) {
+	  error(errSyntaxError, getPos(),
+		"Too many symbols in JBIG2 text region");
+	  delete codeTables;
+	  return;
+	}
+	numSyms += segSize;
       } else if (seg->getType() == jbig2SegCodeTable) {
 	codeTables->append(seg);
       }