An issue was discovered in Adobe Acrobat Reader 2018.009.20050 and earlier versions, 2017.011.30070 and earlier versions, 2015.006.30394 and earlier versions. This vulnerability is an instance of a use after free vulnerability in the JBIG2 decoder. The vulnerability is triggered by a crafted PDF file that contains a malformed JBIG2 stream. Successful exploitation could lead to arbitrary code execution.