Bug 2380929 (CVE-2025-40923)

Summary: CVE-2025-40923 plack-middleware-session: Plack-Middleware-Session insecure session ids
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A random session id generation flaw has been discovered in Plack-Middleware-Session. By default, session ids are generated by 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. Predicable session ids could allow an attacker to gain access to systems.
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Bug Depends On: 2381420, 2381421    
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Description OSIDB Bzimport 2025-07-16 14:01:48 UTC 
Plack-Middleware-Session before version 0.35 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.

Predicable session ids could allow an attacker to gain access to systems.