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

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

No history.

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

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