{"cve":"CVE-2026-13577","nvd":{"published":"2026-07-20T08:16:28.987","modified":"2026-10-24T20:10:00.137","status":"Deferred","description":"Dancer2 versions before 2.2.0 for Perl generate insecure session ids when required CSPRNG modules are unavailable.\n\nDancer2::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.\n\nThe 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).\n\nThese are all low-entropy and easily guessed sources.\n\nThe built-in rand() function is seeded with 32-bits and considered unsuitable for security applications.\n\nPredictable session ids could allow an attacker to gain access to systems.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","score":8.2},"cwes":["CWE-338","CWE-340"],"references":["https://github.com/PerlDancer/Dancer2/blob/v2.1.0/lib/Dancer2/Core/Role/SessionFactory.pm#L142","https://github.com/PerlDancer/Dancer2/issues/1807","https://github.com/PerlDancer/Dancer2/pull/1804","https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes","https://www.cve.org/CVERecord?id=CVE-2026-5080"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:08.599881581+00:00"},"epss":{"cve":"CVE-2026-13577","score":0.0057,"percentile":0.46899,"date":"2026-10-26"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}