Vulnerability-Lookup

CVE-2026-13577 (GCVE-0-2026-13577)

Vulnerability from cvelistv5 – Published: 2026-07-20 07:11 – Updated: 2026-09-20 10:17

Title

Dancer2 versions before 2.2.0 for Perl generate insecure session ids when required CSPRNG modules are unavailable

Summary

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.

Severity

8.2 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-20 13:05 UTC

CWE

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

Assigner

CPANSec CNA under the redhat root

CNA scorecard C 61/100 over 365 records in the last 180 days details

References

5 references

URL	Tags
https://metacpan.org/release/CROMEDOME/Dancer2-2.…	release-notes
https://github.com/PerlDancer/Dancer2/issues/1807	issue-tracking
https://github.com/PerlDancer/Dancer2/pull/1804	issue-tracking
https://github.com/PerlDancer/Dancer2/blob/v2.1.0…
https://www.cve.org/CVERecord?id=CVE-2026-5080	related

Impacted products

1 product

Vendor	Product	Version	CPE status
		Affected: 0 , < 2.2.0 (custom)

Show details on NVD website

JSON

To clipboard

{
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            "value": "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."
          },
          {
            "lang": "es",
            "value": "Las versiones de Dancer2 hasta la 2.1.0 para Perl generan identificadores de sesi\u00f3n inseguros cuando los m\u00f3dulos CSPRNG requeridos no est\u00e1n disponibles.\n\nDancer2::Core::Role::SessionFactory::generate_id recurre silenciosamente a un identificador de sesi\u00f3n derivado de la funci\u00f3n \u2019rand\u2019 incorporada a menos que Math::Random::ISAAC::XS y Crypt::URandom est\u00e9n ambos disponibles.\n\nEl identificador de sesi\u00f3n de respaldo se genera a partir de un hash SHA-1 de una llamada a la funci\u00f3n \u2019rand\u2019 incorporada, la ruta absoluta del m\u00f3dulo Dancer2::Core::Role::SessionFactory, un contador interno, el ID del proceso, la direcci\u00f3n de memoria de la instancia del m\u00f3dulo y una cadena de caracteres mezclada (utilizando la funci\u00f3n List::Util::shuffle, que tambi\u00e9n usa la funci\u00f3n \u2019rand\u2019 incorporada).\n\nTodas estas son fuentes de baja entrop\u00eda y f\u00e1cilmente predecibles.\n\nLa funci\u00f3n \u2019rand()\u2019 incorporada se inicializa con 32 bits y se considera inadecuada para aplicaciones de seguridad.\n\nLos identificadores de sesi\u00f3n predecibles podr\u00edan permitir a un atacante obtener acceso a los sistemas."
          }
        ],
        "id": "CVE-2026-13577",
        "lastModified": "2026-10-24T20:10:00.137",
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      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
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}

FKIE_CVE-2026-13577

Vulnerability from fkie_nvd - Published: 2026-07-20 08:16 - Updated: 2026-10-24 20:10

Severity

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

Summary

References

	URL	Tags
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://github.com/PerlDancer/Dancer2/blob/v2.1.0/lib/Dancer2/Core/Role/SessionFactory.pm#L142
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://github.com/PerlDancer/Dancer2/issues/1807
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://github.com/PerlDancer/Dancer2/pull/1804
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://www.cve.org/CVERecord?id=CVE-2026-5080

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "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"
            }
          ]
        }
      ],
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "Las versiones de Dancer2 hasta la 2.1.0 para Perl generan identificadores de sesi\u00f3n inseguros cuando los m\u00f3dulos CSPRNG requeridos no est\u00e1n disponibles.\n\nDancer2::Core::Role::SessionFactory::generate_id recurre silenciosamente a un identificador de sesi\u00f3n derivado de la funci\u00f3n \u2019rand\u2019 incorporada a menos que Math::Random::ISAAC::XS y Crypt::URandom est\u00e9n ambos disponibles.\n\nEl identificador de sesi\u00f3n de respaldo se genera a partir de un hash SHA-1 de una llamada a la funci\u00f3n \u2019rand\u2019 incorporada, la ruta absoluta del m\u00f3dulo Dancer2::Core::Role::SessionFactory, un contador interno, el ID del proceso, la direcci\u00f3n de memoria de la instancia del m\u00f3dulo y una cadena de caracteres mezclada (utilizando la funci\u00f3n List::Util::shuffle, que tambi\u00e9n usa la funci\u00f3n \u2019rand\u2019 incorporada).\n\nTodas estas son fuentes de baja entrop\u00eda y f\u00e1cilmente predecibles.\n\nLa funci\u00f3n \u2019rand()\u2019 incorporada se inicializa con 32 bits y se considera inadecuada para aplicaciones de seguridad.\n\nLos identificadores de sesi\u00f3n predecibles podr\u00edan permitir a un atacante obtener acceso a los sistemas."
    }
  ],
  "id": "CVE-2026-13577",
  "lastModified": "2026-10-24T20:10:00.137",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 4.2,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-13577",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-20T13:05:03.182340Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-20T08:16:28.987",
  "references": [
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://github.com/PerlDancer/Dancer2/blob/v2.1.0/lib/Dancer2/Core/Role/SessionFactory.pm#L142"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://github.com/PerlDancer/Dancer2/issues/1807"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://github.com/PerlDancer/Dancer2/pull/1804"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-5080"
    }
  ],
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-338"
        },
        {
          "lang": "en",
          "value": "CWE-340"
        }
      ],
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "type": "Secondary"
    }
  ]
}

GHSA-CCC2-34G9-J7RG

Vulnerability from github – Published: 2026-07-20 09:31 – Updated: 2026-09-20 12:30

Details

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.

Severity

8.2 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-13577"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-338"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-20T08:16:28Z",
    "severity": "HIGH"
  },
  "details": "Dancer2 versions through 2.1.0 for Perl generate insecure session ids when CSPRNG modules are unavailable.\n\nDancer2::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.\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.",
  "id": "GHSA-ccc2-34g9-j7rg",
  "modified": "2026-09-20T12:30:26Z",
  "published": "2026-07-20T09:31:08Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-13577"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PerlDancer/Dancer2/issues/1807"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PerlDancer/Dancer2/pull/1804"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PerlDancer/Dancer2/blob/v2.1.0/lib/Dancer2/Core/Role/SessionFactory.pm#L142"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes"
    },
    {
      "type": "WEB",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-5080"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

UBUNTU-CVE-2026-13577 (CVE-2026-13577)

Vulnerability from osv_ubuntu – Published: 2026-07-20 08:16 – Updated: 2026-10-17 09:38 – Source website

Details

Severity

8.2 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-13577	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-13577	REPORT
	https://lists.security.metacpan.org/cve-announce/…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libdancer2-perl",
            "binary_version": "0.166001+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "libdancer2-perl",
        "purl": "pkg:deb/ubuntu/libdancer2-perl@0.166001+dfsg-1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.160003+dfsg-1",
        "0.163000+dfsg-1",
        "0.166001+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libdancer2-perl",
            "binary_version": "0.205002+dfsg-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "libdancer2-perl",
        "purl": "pkg:deb/ubuntu/libdancer2-perl@0.205002+dfsg-2?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.205000+dfsg-1",
        "0.205002+dfsg-1",
        "0.205002+dfsg-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libdancer2-perl",
            "binary_version": "0.300000+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "libdancer2-perl",
        "purl": "pkg:deb/ubuntu/libdancer2-perl@0.300000+dfsg-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.208001+dfsg-1",
        "0.208002+dfsg-1",
        "0.300000+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libdancer2-perl",
            "binary_version": "0.301004+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libdancer2-perl",
        "purl": "pkg:deb/ubuntu/libdancer2-perl@0.301004+dfsg-1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.300005+dfsg-1",
        "0.301004+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libdancer2-perl",
            "binary_version": "1.1.0+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libdancer2-perl",
        "purl": "pkg:deb/ubuntu/libdancer2-perl@1.1.0+dfsg-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.400001+dfsg-1",
        "1.0.0+dfsg-1",
        "1.1.0+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libdancer2-perl",
            "binary_version": "2.1.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "libdancer2-perl",
        "purl": "pkg:deb/ubuntu/libdancer2-perl@2.1.0-1?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.1.2+dfsg-1",
        "2.1.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libdancer2-perl",
            "binary_version": "1.1.2+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libdancer2-perl",
        "purl": "pkg:deb/ubuntu/libdancer2-perl@1.1.2+dfsg-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.1.2+dfsg-1"
      ]
    }
  ],
  "aliases": [],
  "details": "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.",
  "id": "UBUNTU-CVE-2026-13577",
  "modified": "2026-10-17T09:38:00Z",
  "published": "2026-07-20T08:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-13577"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-13577"
    },
    {
      "type": "REPORT",
      "url": "https://lists.security.metacpan.org/cve-announce/msg/41975698/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-13577"
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-13577 (GCVE-0-2026-13577)

FKIE_CVE-2026-13577

GHSA-CCC2-34G9-J7RG

UBUNTU-CVE-2026-13577 (CVE-2026-13577)

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