Vulnerability Description
Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely. The default session id generator returns a SHA-1 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. Predictable session ids could allow an attacker to gain access to systems. Plack::Middleware::Session::Simple is intended to be compatible with Plack::Middleware::Session, which had a similar security issue CVE-2025-40923.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Kazeburo | Plack\ | < 0.05, \ |
Related Weaknesses (CWE)
References
- https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53Patch
- https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4Issue TrackingPatch
- https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/sourcIssue TrackingProduct
- https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.05/chang
- https://security.metacpan.org/docs/guides/random-data-for-security.htmlThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2025-40923Third Party Advisory
FAQ
What is CVE-2025-40926?
CVE-2025-40926 is a vulnerability with a CVSS score of 9.8 (CRITICAL). Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely. The default session id generator returns a SHA-1 hash seeded with the built-in rand function, the ep...
How severe is CVE-2025-40926?
CVE-2025-40926 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2025-40926?
Check the references section above for vendor advisories and patch information. Affected products include: Kazeburo Plack\.