CVE-2026-5080: Dancer::Session::Abstract versions through 1.3522 for Perl generates session ids insecurely

[Robert Rothenberg <rrwo () cpansec org>]

========================================================================
CVE-2026-5080                                        CPAN Security Group
========================================================================

        CVE ID:  CVE-2026-5080
  Distribution:  Dancer
      Versions:  through 1.3522

      MetaCPAN:  https://metacpan.org/dist/Dancer
      VCS Repo:  https://github.com/PerlDancer/Dancer


Dancer::Session::Abstract versions through 1.3522 for Perl generates
session ids insecurely

Description
-----------
Dancer::Session::Abstract versions through 1.3522 for Perl generates
session ids insecurely.

The session id is generated from summing the character codepoints of
the absolute pathname with the process id, the epoch time and calls to
the built-in rand() function to return a number between 0 and
999-billion, and concatenating that result three times.

The path name might be known or guessed by an attacker, especially for
applications known to be written using Dancer with standard
installation locations.

The epoch time can be guessed by an attacker, and may be leaked in the
HTTP header.

The process id comes from a small set of numbers, and workers may have
sequential process ids.

The built-in rand() function is seeded with 32-bits and is considered
unsuitable for security applications.

Predictable session ids could allow an attacker to gain access to
systems.

Problem types
-------------
- CWE-340 Generation of Predictable Numbers or Identifiers
- CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator

Workarounds
-----------
Apply the linked patch.


References
----------
https://security.metacpan.org/patches/D/Dancer/1.3522/CVE-2026-5080-r1.patch
https://metacpan.org/release/BIGPRESH/Dancer-1.3522/source/lib/Dancer/Session/Abstract.pm#L85-102