CVE-2025-40926
Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely
Description
Plack::Middleware::Session::Simple versions before 0.05 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. Predictable 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.
INFO
Published Date :
March 5, 2026, 2:16 a.m.
Last Modified :
March 12, 2026, 12:16 a.m.
Remotely Exploit :
Yes !
Source :
9b29abf9-4ab0-4765-b253-1875cd9b441e
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update Plack::Middleware::Session::Simple to version 0.05 or later.
- Ensure the random number generator is cryptographically secure.
- Use a strong source for session ID generation.
- Avoid using epoch time or PID for seeding.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-40926.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-40926 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-40926
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-40926 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-40926 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 9b29abf9-4ab0-4765-b253-1875cd9b441e
Mar. 12, 2026
Action Type Old Value New Value Changed 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. Plack::Middleware::Session::Simple versions before 0.05 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. Predictable 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. Added Reference https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.05/changes -
Initial Analysis by [email protected]
Mar. 09, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:kazeburo:plack::middleware::session::simple:*:*:*:*:*:perl:*:* versions up to (excluding) 0.05 Added Reference Type CPANSec: https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patch Types: Patch Added Reference Type CPANSec: https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4 Types: Issue Tracking, Patch Added Reference Type CPANSec: https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pm#L43 Types: Issue Tracking, Product Added Reference Type CPANSec: https://security.metacpan.org/docs/guides/random-data-for-security.html Types: Third Party Advisory Added Reference Type CPANSec: https://www.cve.org/CVERecord?id=CVE-2025-40923 Types: Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Mar. 05, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 9b29abf9-4ab0-4765-b253-1875cd9b441e
Mar. 05, 2026
Action Type Old Value New Value Added 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. Added CWE CWE-338 Added CWE CWE-340 Added Reference https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patch Added Reference https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4 Added Reference https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pm#L43 Added Reference https://security.metacpan.org/docs/guides/random-data-for-security.html Added Reference https://www.cve.org/CVERecord?id=CVE-2025-40923