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.
Advisories
Source ID Title
EUVD EUVD EUVD-2025-21693 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.
Fixes

Solution

Users are advised to upgrade to Plack-Middleware-Session v0.35 or later.


Workaround

Users who are unable to upgrade are advised to change the sid_generator attribute of Plack::Session::State to a function that returns a securely generated session id based on a secure source of entropy from the system.

History

Tue, 04 Nov 2025 22:30:00 +0000

Type Values Removed Values Added
References

Wed, 16 Jul 2025 21:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 16 Jul 2025 13:15:00 +0000

Type Values Removed Values Added
Description 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.
Title Plack-Middleware-Session before version 0.35 for Perl generates session ids insecurely
Weaknesses CWE-338
CWE-340
References

cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2025-11-04T21:10:20.704Z

Reserved: 2025-04-16T09:05:34.362Z

Link: CVE-2025-40923

cve-icon Vulnrichment

Updated: 2025-11-04T21:10:20.704Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-07-16T13:15:23.997

Modified: 2025-11-04T22:16:12.360

Link: CVE-2025-40923

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.