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CVE-2026-13577

Dancer2 · Vulnerability

cve-program · severity unknownCVSS unknownCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-13577

Published

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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-13577

Published

Dancer2

https://cpan.org/modules

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "collectionURL": "https://cpan.org/modules",
                    "defaultStatus": "unaffected",
                    "modules": [
                        "Dancer2"
                    ],
                    "packageName": "Dancer2",
                    "packageURL": "pkg:cpan/Dancer2",
                    "programFiles": [
                        "lib/Dancer2/Core/Role/SessionFactory.pm"
                    ],
                    "programRoutines": [
                        {
                            "name": "Dancer2::Core::Role::SessionFactory::generate_id"
                        }
                    ],
                    "repo": "https://github.com/PerlDancer/Dancer2",
                    "versions": [
                        {
                            "lessThan": "2.2.0",
                            "status": "affected",
                            "version": "0",
                            "versionType": "custom"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON