CVE-2025-40923

Plack-Middleware-Session before version 0.35 for Perl generates session ids insecurely

HIGH
7.3
CVSS Score
Published: July 16, 2025 at 01:05 PM UTC
Updated: June 17, 2026 at 09:22 AM UTC
1 product affected across 1 vendorPlack::Middleware::Session

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Severity
HIGH7.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.01 ≤ v < 0.350.01
Affected range stops below 0.35, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.3HIGHCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-338CWE-340

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