CVE-2026-13577
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).
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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.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
- Puntuación base: 8.2
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.57%
- Percentil entre todas las CVEs puntuadas: 45
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1190Exploit Public-Facing Applicationinitial access85 % - Impacto principal
T1078.001Default Accountsstealth · persistence · privilege escalation · initial access90 % - Impacto secundario
T1552.007Container APIcredential access75 %
AV:N, PR:N, UI:N indica explotación remota sin privilegios (T1190). Sesiones predecibles permiten falsificación de identidad (T1078.001) y acceso a datos de sesión (T1552.007 credential access).
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-338, CWE-340
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-13577",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-13577",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-07-20T13:05:03.182340Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 8.2,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "LOW"
},
"impactScore": 4.2,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"affectedData": [
{
"repo": "https://github.com/PerlDancer/Dancer2",
"modules": [
"Dancer2"
],
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "2.2.0",
"versionType": "custom"
}
],
"packageURL": "pkg:cpan/Dancer2",
"packageName": "Dancer2",
"programFiles": [
"lib/Dancer2/Core/Role/SessionFactory.pm"
],
"collectionURL": "https://cpan.org/modules",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "Dancer2::Core::Role::SessionFactory::generate_id"
}
]
}
]
}
],
"published": "2026-07-20T08:16:28.987",
"references": [
{
"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",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"description": [
{
"lang": "en",
"value": "CWE-338"
},
{
"lang": "en",
"value": "CWE-340"
}
]
}
],
"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."
}
],
"lastModified": "2026-09-20T11:16:56.817",
"sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}