HTTP::Body versions before 1.23_01 for Perl allow CPU exhaustion via quadratic rescanning of a multipart body with a missing or malformed boundary

HTTP::Body versions before 1.23_01 for Perl allow CPU exhaustion via quadratic rescanning of a multipart body with a missing or malformed boundary.

Before the first part, and between parts, the multipart parser searches the whole buffered body for the next boundary. On a miss it keeps everything and searches again from the start when the next chunk arrives. A body with no boundary, or with a delimiter followed by neither CRLF nor "--", is therefore rescanned on every chunk, taking time quadratic in its size.

A remote attacker can exhaust worker CPU with a few such requests.