CVE-2025-40923
highpriority · track · 0EPSS 0.004 · 33 %ileEUEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.7–7.3
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (16)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/cve-2025-40923cnnvd
- https://github.com/plack/Plack-Middleware-Session/commit/1fbfbb355e34e7f4b3906f66cf958cedadd2b9be.patchcnnvd
- https://github.com/plack/Plack-Middleware-Session/pull/52cnnvd
- https://metacpan.org/dist/Plack-Middleware-Session/changesPatchcnnvd
- https://metacpan.org/release/MIYAGAWA/Plack-Middleware-Session-0.34/source/lib/Plack/Session/State.pm#L22cnnvd
- https://security.metacpan.org/docs/guides/random-data-for-security.htmlcnnvd
- https://vigilance.fr/vulnerability/Perl-Plack-Middleware-Session-weak-encryption-via-Session-Id-Generation-48233cnnvd
- https://github.com/plack/Plack-Middleware-Session/commit/1fbfbb355e34e7f4b3906f66cf958cedadd2b9be.patchenisa_euvd
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