CVE-2025-65015
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions from 1.3.3 to before 1.3.5 and from 1.4.0 to before 1.4.2, the ExceededSizeError exception messages are embedded with non-decoded JWT token parts and may cause Python logging to record an arbitrarily large, forged JWT payload. In situations where a misconfigured — or entirely absent — production-grade web server sits in front of a Python web application, an attacker may be able to send arbitrarily large bearer tokens in the HTTP request headers.
Leer descripción completaMostrar menos
When this occurs, Python logging or diagnostic tools (e.g., Sentry) may end up processing extremely large log messages containing the full JWT header during the joserfc.jwt.decode() operation. The same behavior also appears when validating claims and signature payload sizes, as the library raises joserfc.errors.ExceededSizeError() with the full payload embedded in the exception message. Since the payload is already fully loaded into memory at this stage, the library cannot prevent or reject it. This issue has been patched in versions 1.3.5 and 1.4.2.
CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Puntuación base: 9.2
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.41%
- Percentil entre todas las CVEs puntuadas: 33
- 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
T1499.004Application or System Exploitationimpact90 %
AV:N/PR:N/UI:N permite explotación remota sin privilegios (T1190). VA:H/SA:H indica DoS por consumo de recursos: tokens JWT enormes causan saturación de memoria y logging excesivo (T1499.004, Endpoint Denial of Service).
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)
CWE
- CWE-770
Referencias
- https://github.com/authlib/joserfc/commit/63932f169d924caffafa761af2122b82059017f7
- https://github.com/authlib/joserfc/commit/673c8743fd0605b0e1de6452be6cba75f44e466b
- https://github.com/authlib/joserfc/releases/tag/1.3.5
- https://github.com/authlib/joserfc/releases/tag/1.4.2
- https://github.com/authlib/joserfc/security/advisories/GHSA-frfh-8v73-gjg4
- https://github.com/authlib/joserfc/security/advisories/GHSA-frfh-8v73-gjg4
JSON original (NVD)
Mostrar
{
"id": "CVE-2025-65015",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2025-65015",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2025-11-19T17:11:59.909842Z"
}
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.5,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"exploitabilityScore": 3.9
}
],
"cvssMetricV40": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
"Recovery": "NOT_DEFINED",
"baseScore": 9.2,
"Automatable": "NOT_DEFINED",
"attackVector": "NETWORK",
"baseSeverity": "CRITICAL",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"exploitMaturity": "NOT_DEFINED",
"providerUrgency": "NOT_DEFINED",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"privilegesRequired": "NONE",
"subIntegrityImpact": "NONE",
"vulnIntegrityImpact": "NONE",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"subAvailabilityImpact": "HIGH",
"vulnAvailabilityImpact": "HIGH",
"availabilityRequirement": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"subConfidentialityImpact": "NONE",
"vulnConfidentialityImpact": "NONE",
"confidentialityRequirement": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED"
}
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "authlib",
"product": "joserfc",
"versions": [
{
"status": "affected",
"version": ">= 1.3.3, < 1.3.5"
},
{
"status": "affected",
"version": ">= 1.4.0, < 1.4.2"
}
]
}
]
}
],
"published": "2025-11-18T23:15:56.513",
"references": [
{
"url": "https://github.com/authlib/joserfc/commit/63932f169d924caffafa761af2122b82059017f7",
"tags": [
"Patch"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/authlib/joserfc/commit/673c8743fd0605b0e1de6452be6cba75f44e466b",
"tags": [
"Patch"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/authlib/joserfc/releases/tag/1.3.5",
"tags": [
"Release Notes"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/authlib/joserfc/releases/tag/1.4.2",
"tags": [
"Release Notes"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/authlib/joserfc/security/advisories/GHSA-frfh-8v73-gjg4",
"tags": [
"Exploit",
"Vendor Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/authlib/joserfc/security/advisories/GHSA-frfh-8v73-gjg4",
"tags": [
"Exploit",
"Vendor Advisory"
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Analyzed",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-770"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions from 1.3.3 to before 1.3.5 and from 1.4.0 to before 1.4.2, the ExceededSizeError exception messages are embedded with non-decoded JWT token parts and may cause Python logging to record an arbitrarily large, forged JWT payload. In situations where a misconfigured — or entirely absent — production-grade web server sits in front of a Python web application, an attacker may be able to send arbitrarily large bearer tokens in the HTTP request headers. When this occurs, Python logging or diagnostic tools (e.g., Sentry) may end up processing extremely large log messages containing the full JWT header during the joserfc.jwt.decode() operation. The same behavior also appears when validating claims and signature payload sizes, as the library raises joserfc.errors.ExceededSizeError() with the full payload embedded in the exception message. Since the payload is already fully loaded into memory at this stage, the library cannot prevent or reject it. This issue has been patched in versions 1.3.5 and 1.4.2."
}
],
"lastModified": "2026-06-17T09:55:20.877",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:hsiaoming:joserfc:*:*:*:*:*:python:*:*",
"vulnerable": true,
"matchCriteriaId": "B00A046D-0ED8-4DBA-9CB9-FBD848071D8A",
"versionEndExcluding": "1.3.5",
"versionStartIncluding": "1.3.3"
},
{
"criteria": "cpe:2.3:a:hsiaoming:joserfc:*:*:*:*:*:python:*:*",
"vulnerable": true,
"matchCriteriaId": "25663E58-FE1C-44E1-9051-A2A388EB2595",
"versionEndExcluding": "1.4.2",
"versionStartIncluding": "1.4.0"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "security-advisories@github.com"
}