Pod::Text versions before 6.1.1 for Perl allow CPU and memory exhaustion formatting a POD document whose =over nesting drives the margin to the output width. Each =over adds its indent to the margin, which wrap() subtracts from the output width to get the space available for text. When that space reaches zero, the line-splitting substitution matches the empty string, and the loop consumes no input while appending the margin padding on every pass. Formatting an attacker-supplied POD document never returns, and the output grows until memory is exhausted.