Heap-based buffer overflow in the XSLT engine in Adobe Reader and Acrobat 9.x before 9.5.3, 10.x before 10.1.5, and 11.x before 11.0.1 allows attackers to execute arbitrary code or cause a denial of service (memory corruption) via a PDF file containing an XSL file that triggers memory corruption when the lang function processes XML data with a crafted node-set.