CVE-2025-40926

Description

Plack::Middleware::Session::Simple versions through 0.04 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. Plack::Middleware::Session::Simple is intended to be compatible with Plack::Middleware::Session, which had a similar security issue CVE-2025-40923.

PUBLISHED Reserved 2025-04-16 | Published 2026-03-05 | Updated 2026-03-05 | Assigner CPANSec

Problem types

CWE-340 Generation of Predictable Numbers or Identifiers

CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator

Product status

References

metacpan.org/...ource/lib/Plack/Middleware/Session/Simple.pm

github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4 issue-tracking

github.com/...760bb358b8f53e52cf415888a4ac858fd99bb24e.patch patch

www.cve.org/CVERecord?id=CVE-2025-40923 vendor-advisory related vdb-entry

security.metacpan.org/...uides/random-data-for-security.html technical-description

cve.org (CVE-2025-40926)

nvd.nist.gov (CVE-2025-40926)

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