CVE-2025-40926

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

P

lack::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.

References

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

Configurations

No configuration.

History

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 : 2026-03-05 19:38

NVD link : CVE-2025-40926

Mitre link : CVE-2025-40926

CVE.ORG link : CVE-2025-40926

JSON object : View

Products Affected

No product.

CWE

CWE-338

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

CWE-340

Generation of Predictable Numbers or Identifiers

{"id": "CVE-2025-40926", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}]}, "published": "2026-03-05T02:16:39.790", "references": [{"url": "https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patch", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pm#L43", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "https://security.metacpan.org/docs/guides/random-data-for-security.html", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "https://www.cve.org/CVERecord?id=CVE-2025-40923", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "description": [{"lang": "en", "value": "CWE-338"}, {"lang": "en", "value": "CWE-340"}]}], "descriptions": [{"lang": "en", "value": "Plack::Middleware::Session::Simple versions through 0.04 for Perl generates session ids insecurely.\n\nThe 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.\n\nPredicable session ids could allow an attacker to gain access to systems.\n\nPlack::Middleware::Session::Simple is intended to be compatible with Plack::Middleware::Session, which had a similar security issue CVE-2025-40923."}], "lastModified": "2026-03-05T19:38:53.383", "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}