CVE-2025-40926
Last modified
CVE-2025-40926 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 0.43% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Kazeburo | Plack\ | < 0.05 | Middleware\ |
References
- https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4Issue Tracking, Patch
- https://security.metacpan.org/docs/guides/random-data-for-security.htmlThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2025-40923Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
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