Starch versions 0.14 and earlier generate session ids insecurely. The default session id generator returns a SHA-1 hash seeded with a counter, the epoch time, the built-in rand function, the PID, and internal Perl reference addresses. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. Predicable session ids could allow an attacker to gain access to systems.
https://metacpan.org/dist/Starch/source/lib/Starch/Manager.pm
https://github.com/bluefeet/Starch/pull/5
https://github.com/bluefeet/Starch/commit/5573449e64e0660f7ee209d1eab5881d4ccbee3b.patch