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Critical 9.8Published Mar 5, 2026

CVE-2025-40926Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely.

Updated under an hour ago ()

Does this affect you?

It affects kazeburo plack::middleware::session::simple. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
9.8 CRITICAL (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-338, CWE-340
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Not given
NVD analysis
Modified
Record last updated
Jun 17, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
kazeburo plack::middleware::session::simple
kazeburo:plack::middleware::session::simple
before 0.05
NVD

References

  • patch
  • issue-tracking, patch
  • issue-tracking, product
  • third-party-advisory
  • third-party-advisory

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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