{"api_version":"1","generated_at":"2026-07-23T12:58:17+00:00","cve":"CVE-2026-13577","urls":{"html":"https://cve.report/CVE-2026-13577","api":"https://cve.report/api/cve/CVE-2026-13577.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-13577","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-13577"},"summary":{"title":"Dancer2 versions through 2.1.0 for Perl generate insecure session ids when required CSPRNG modules are unavailable","description":"Dancer2 versions through 2.1.0 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.","state":"PUBLISHED","assigner":"CPANSec","published_at":"2026-07-20 08:16:28","updated_at":"2026-07-22 12:17:09"},"problem_types":["CWE-338","CWE-340","CWE-340 CWE-340 Generation of Predictable Numbers or Identifiers","CWE-338 CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator"],"metrics":[{"version":"3.1","source":"ADP","type":"DECLARED","score":"8.2","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","data":{"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"}},{"version":"3.1","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","score":"8.2","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://www.cve.org/CVERecord?id=CVE-2026-5080","name":"https://www.cve.org/CVERecord?id=CVE-2026-5080","refsource":"9b29abf9-4ab0-4765-b253-1875cd9b441e","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/PerlDancer/Dancer2/blob/v2.1.0/lib/Dancer2/Core/Role/SessionFactory.pm#L142","name":"https://github.com/PerlDancer/Dancer2/blob/v2.1.0/lib/Dancer2/Core/Role/SessionFactory.pm#L142","refsource":"9b29abf9-4ab0-4765-b253-1875cd9b441e","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-13577","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-13577","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"CROMEDOME","product":"Dancer2","version":"affected 2.1.0 custom","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[{"source":"CNA","title":"","value":"Ensure Crypt::URandom and Math::Random::ISAAC::XS modules are installed in the application PERL5LIB path.","time":"","lang":"en"}],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"13577","cve":"CVE-2026-13577","epss":"0.002580000","percentile":"0.174250000","score_date":"2026-07-22","updated_at":"2026-07-23 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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."}],"impacts":[{"capecId":"CAPEC-115","descriptions":[{"lang":"en","value":"CAPEC-115 Authentication Bypass"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-340","description":"CWE-340 Generation of Predictable Numbers or Identifiers","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-338","description":"CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-07-22T12:00:11.288Z","orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","shortName":"CPANSec"},"references":[{"url":"https://github.com/PerlDancer/Dancer2/blob/v2.1.0/lib/Dancer2/Core/Role/SessionFactory.pm#L142"},{"tags":["related"],"url":"https://www.cve.org/CVERecord?id=CVE-2026-5080"}],"source":{"discovery":"UNKNOWN"},"title":"Dancer2 versions through 2.1.0 for Perl generate insecure session ids when required CSPRNG modules are unavailable","workarounds":[{"lang":"en","value":"Ensure Crypt::URandom and Math::Random::ISAAC::XS modules are installed in the application PERL5LIB path."}],"x_generator":{"engine":"cpansec-cna-tool 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Generator"],"metrics":{"cvssMetricV31":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":4.2}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-07-20T13:05:03.182340Z","id":"CVE-2026-13577","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"13577","Ordinal":"1","Title":"Dancer2 versions through 2.1.0 for Perl generate insecure sessio","CVE":"CVE-2026-13577","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"13577","Ordinal":"1","NoteData":"Dancer2 versions through 2.1.0 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.","Type":"Description","Title":"Dancer2 versions through 2.1.0 for Perl generate insecure sessio"}]}}}