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. The vulnerability is a result of untrusted input that is used to calculate an array index; the calculation occurs in the image conversion module, when processing GIF files. The vulnerability leads to an operation that can write to a memory location that is outside of the memory addresses allocated for the data structure. The specific scenario leads to a write access to a memory location that does not belong to the relevant process address space.