CVE-2025-62706

{
  "id": "CVE-2025-62706",
  "sourceIdentifier": "[email protected]",
  "published": "2025-10-22T22:15:35.557",
  "lastModified": "2026-10-19T13:10:00.110",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib’s JWE zip=DEF path performs unbounded DEFLATE decompression. A very small ciphertext can expand into tens or hundreds of megabytes on decrypt, allowing an attacker who can supply decryptable tokens to exhaust memory and CPU and cause denial of service. This issue has been patched in version 1.6.5. Workarounds for this issue involve rejecting or stripping zip=DEF for inbound JWEs at the application boundary, forking and add a bounded decompression guard via decompressobj().decompress(data, MAX_SIZE)) and returning an error when output exceeds a safe limit, or enforcing strict maximum token sizes and fail fast on oversized inputs; combine with rate limiting."
    },
    {
      "lang": "es",
      "value": "Authlib es una biblioteca Python que construye servidores OAuth y OpenID Connect. Antes de la versión 1.6.5, la ruta JWE zip=DEF de Authlib realiza una descompresión DEFLATE ilimitada. Un texto cifrado muy pequeño puede expandirse a decenas o cientos de megabytes al descifrar, permitiendo a un atacante que puede suministrar tokens descifrables agotar la memoria y la CPU y causar denegación de servicio. Este problema ha sido parcheado en la versión 1.6.5. Las soluciones alternativas para este problema implican rechazar o eliminar zip=DEF para los JWE entrantes en el límite de la aplicación, bifurcar y añadir una protección de descompresión limitada a través de decompressobj().decompress(data, MAX_SIZE)) y devolver un error cuando la salida excede un límite seguro, o aplicar tamaños máximos de token estrictos y fallar rápidamente en entradas sobredimensionadas; combinar con la limitación de velocidad."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "authlib",
          "product": "authlib",
          "versions": [
            {
              "version": "< 1.6.5",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2025-10-23T15:44:18.329916Z",
          "id": "CVE-2025-62706",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        },
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:authlib:authlib:*:*:*:*:*:*:*:*",
              "versionEndExcluding": "1.6.5",
              "matchCriteriaId": "B4367901-9190-47A3-88FA-173EE7C2FB13"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/authlib/authlib/commit/e0863d5129316b1790eee5f14cece32a03b8184d",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/authlib/authlib/security/advisories/GHSA-g7f3-828f-7h7m",
      "source": "[email protected]",
      "tags": [
        "Exploit",
        "Mitigation",
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00032.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ]
}