CVE-2026-13577

[CVE catalog]

Severity

High · CVSS 8.2CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

Published

Jul 20, 2026, 7:11:10 AM UTC

Source

[NVD] · [CVE record]

EPSS

0.57% · Oct 25, 2026

Dancer2 versions before 2.2.0 for Perl generate insecure session ids when required CSPRNG modules are unavailable. Dancer2::Core::Role::SessionFactory::generate_id silently falls back to a built-in rand-derived session id unless both Math::Random::ISAAC::XS and Crypt::URandom are available. 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.