Memory corruption via stale Perl stack pointer

Use-after-free in Text::CSV_XS before 1.62 allows local users to trigger memory corruption when registered callbacks reallocate the Perl argument stack. The Parse, print, getline, and getline_all XS methods retain an argument-stack pointer across callback execution, then write the return value through that stale pointer after a callback forces stack reallocation. Exposure requires a registered callback that grows the stack; callback-free use is unaffected, while affected callers can receive the object instead of parsed data, corrupt memory, or crash.