CVE-2025-40931: Chorny apache::session::generate::md5

Critical severity, CVSS 9.1. EPSS: 0.6% chance of exploitation in the next 30 days.

Apache::Session::Generate::MD5 versions through 1.94 for Perl create insecure session id. Apache::Session::Generate::MD5 generates session ids insecurely. The default session id generator returns a MD5 hash seeded with the built-in rand() function, the epoch time, and the PID. 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. Note that the libapache-session-perl package in some Debian-based Linux distributions may be patched to use Crypt::URandom.

Affected products

• Chorny apache::session::generate::md5: up to and including 1.94

Published 2026-03-05. Last modified 2026-06-17.