# CVE-2026-13577

## Summary

- **CVE ID:** CVE-2026-13577
- **Severity:** UNKNOWN
- **CVSS Score:** 0.01 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H)
- **CWE:** CWE-340, CWE-338
- **Published:** Jul 20, 2026
- **Last Modified:** Jul 22, 2026

## Description

Dancer2 versions through 2.1.0 for Perl generate insecure session ids when CSPRNG modules are unavailable.

Dancer2::Core::Role::SessionFactory::generate_id silently falls back to a built-in rand-derived session id when both Math::Random::ISAAC::XS and Crypt::URandom are unavailable.

The fallback session id is generated from a SHA-1 hash of a call to the built-in rand function, the absolute path of the Dancer2::Core::Role::SessionFactory module, an internal counter, the process id, the module instance memory address, and a shuffled string of characters (using the List::Util::shuffle function, which also uses the built-in rand function).

These are all low-entropy and easily guessed sources.

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

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

## Affected Products

- CROMEDOME — Dancer2 (0)

## References

- [CNA](https://github.com/PerlDancer/Dancer2/blob/v2.1.0/lib/Dancer2/Core/Role/SessionFactory.pm#L142)
- [CNA](https://www.cve.org/CVERecord?id=CVE-2026-5080)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.45%
- **EPSS Percentile:** 37.9

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._