CGI versions before 5.00 for Perl allow memory, CPU and disk exhaustion via missing or unenforced request size, parameter and upload limits.

$CGI::POST_MAX defaults to no limit, and when set is not enforced for chunked multipart bodies or for the boundary line of a multipart body without a boundary= parameter. Bodies saved as PUTDATA, POSTDATA or PATCHDATA uploads are read into memory in one go, and nothing limits the number of parameters or uploads.