PAGI::Middleware::Session::Store::Cookie versions through 0.001003 for Perl generates random bytes insecurely.

PAGI::Middleware::Session::Store::Cookie attempts to read bytes from the /dev/urandom device directly. If that fails (for example, on systems without the device, such as Windows), then it will emit a warning that recommends the user install Crypt::URandom, and then return a string of random bytes generated by the built-in rand function, which is unsuitable for cryptographic applications.

This modules does not use the Crypt::URandom module, and installing it will not fix the problem.

The random bytes are used for generating an initialisation vector (IV) to encrypt the cookie.

A predictable IV may make it easier for malicious users to decrypt and tamper with the session data that is stored in the cookie.

References

• https://nvd.nist.gov/vuln/detail/CVE-2026-5087
• https://metacpan.org/release/JJNAPIORK/PAGI-Middleware-Session-Store-Cookie-0.001003/source/lib/PAGI/Middleware/Session/Store/Cookie.pm#L156-173
• https://metacpan.org/release/JJNAPIORK/PAGI-Middleware-Session-Store-Cookie-0.001004/changes
• http://www.openwall.com/lists/oss-security/2026/03/31/10