Unrated severityNVD Advisory· Published Mar 5, 2026· Updated Apr 21, 2026
Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely
CVE-2025-40926
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.
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LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
2- Range: <0.05
- KAZEBURO/Plack::Middleware::Session::Simplev5Range: 0
Patches
Vulnerability mechanics
References
6- github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patchmitrepatch
- www.cve.org/CVERecordmitrevendor-advisoryrelatedvdb-entry
- github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4mitreissue-tracking
- metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.05/changesmitrerelease-notes
- security.metacpan.org/docs/guides/random-data-for-security.htmlmitretechnical-description
- metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pmmitre
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