REDHAT-BUG-2344615: Medium severity GNU Libtasn1 vulnerability

The issue is twofold: decoding a DER input with sequences and locating a specific element in a sequence. Even though a DER sequence is conceptually an array, in libtasn1 it is represented as a linked list, whose elements are assigned a string name, such as "?1". Therefore a simple lookup of an element at a given position is linear O(N) time complexity. When decoding a DER sequence, in each step libtasn1 looks up the parent node, recorded on the first element, which requires a backward linear search, resulting in O(N^2) time complexity.