When an algorithm requires x bytes of memory for a given input it shouldn't matter whether a given implementation of that algorithm uses x bytes of implicit stack from recursion, x bytes of heap allocated with malloc, or something else; however unfortunately in various poor programming language implementations this does make a big difference, such as the case described in the article. The problem is not recursion nor the algorithm, the problem is the poor implementation of recursion in their C compiler, and as such it can be avoided by expressing the same algorithm without that C recursion (which is trivial). Even in the unlikely event that such an expression exhausted available memory (implausible), it would not be a security issue.
