An issue was discovered in Adobe Acrobat and Reader: 2017.012.20098 and earlier versions, 2017.011.30066 and earlier versions, 2015.006.30355 and earlier versions, and 11.0.22 and earlier versions. This vulnerability is an instance of a security bypass vulnerability for a certain file-type extension. Acrobat maintains both a blacklist and whitelist (the user can specify an allowed attachment). However, any file extensions that are neither on the blacklist nor the whitelist can still be opened after displaying a warning prompt.