Stream.cc in Xpdf, as used in products such as gpdf, kpdf, pdftohtml, poppler, teTeX, CUPS, libextractor, and others, allows attackers to modify memory and possibly execute arbitrary code via a DCTDecode stream with (1) a large "number of components" value that is not checked by DCTStream::readBaselineSOF or DCTStream::readProgressiveSOF, (2) a large "Huffman table index" value that is not checked by DCTStream::readHuffmanTables, and (3) certain uses of the scanInfo.numComps value by DCTStream::readScanInfo.