CVE-2025-40926

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.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patch	Patch
https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4	Issue Tracking Patch
https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pm#L43	Issue Tracking Product
https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.05/changes
https://security.metacpan.org/docs/guides/random-data-for-security.html	Third Party Advisory
https://www.cve.org/CVERecord?id=CVE-2025-40923	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:kazeburo:plack\:\:middleware\:\:session\:\:simple:*:*:*:*:*:perl:*:*

History

12 Mar 2026, 00:16

Type	Values Removed	Values Added
References		() https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.05/changes -
Summary		(es) Las versiones de Plack::Middleware::Session::Simple hasta la 0.04 para Perl generan identificadores de sesión de forma insegura. El generador predeterminado de identificadores de sesión devuelve un hash SHA-1 inicializado con la función rand incorporada, el tiempo epoch y el PID. El PID provendrá de un pequeño conjunto de números, y el tiempo epoch puede ser adivinado, si no se filtra del encabezado HTTP Date. La función rand incorporada no es adecuada para uso criptográfico. Los identificadores de sesión predecibles podrían permitir a un atacante obtener acceso a los sistemas. Plack::Middleware::Session::Simple está diseñado para ser compatible con Plack::Middleware::Session, que tuvo un problema de seguridad similar CVE-2025-40923.
Summary	(en) 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.	(en) 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.

09 Mar 2026, 14:34

Type	Values Removed	Values Added
First Time		Kazeburo Kazeburo plack\
CPE		cpe:2.3:a:kazeburo:plack\:\:middleware\:\:session\:\:simple::::::perl::*
References	~~() https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patch -~~	() https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patch - Patch
References	~~() https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4 -~~	() https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4 - Issue Tracking, Patch
References	~~() https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pm#L43 -~~	() https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pm#L43 - Issue Tracking, Product
References	~~() https://security.metacpan.org/docs/guides/random-data-for-security.html -~~	() https://security.metacpan.org/docs/guides/random-data-for-security.html - Third Party Advisory
References	~~() https://www.cve.org/CVERecord?id=CVE-2025-40923 -~~	() https://www.cve.org/CVERecord?id=CVE-2025-40923 - Third Party Advisory

05 Mar 2026, 19:15

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 9.8

05 Mar 2026, 02:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-03-05 02:16

Updated : 2026-03-12 00:16

NVD link : CVE-2025-40926

Mitre link : CVE-2025-40926

CVE.ORG link : CVE-2025-40926

JSON object : View

Products Affected

kazeburo

plack\

CWE

CWE-338

Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

CWE-340

Generation of Predictable Numbers or Identifiers

9.8 /10