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.
Metrics
Affected Vendors & Products
| Source | ID | Title |
|---|---|---|
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. |
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.
Tue, 04 Nov 2025 22:30:00 +0000
| Type | Values Removed | Values Added |
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| References |
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Wed, 16 Jul 2025 21:15:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
cvssV3_1
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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 |
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| References |
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Status: PUBLISHED
Assigner: CPANSec
Published:
Updated: 2025-11-04T21:10:20.704Z
Reserved: 2025-04-16T09:05:34.362Z
Link: CVE-2025-40923
Updated: 2025-11-04T21:10:20.704Z
Status : Awaiting Analysis
Published: 2025-07-16T13:15:23.997
Modified: 2025-11-04T22:16:12.360
Link: CVE-2025-40923
No data.
OpenCVE Enrichment
No data.
EUVD