CVE-2026-6550

{
  "id": "CVE-2026-6550",
  "sourceIdentifier": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
  "published": "2026-04-20T20:16:49.283",
  "lastModified": "2026-10-26T22:10:00.163",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Cryptographic algorithm downgrade in the caching layer of Amazon AWS Encryption SDK for Python before version 3.3.1 and before version  4.0.5 might allow an authenticated local threat actor to bypass key commitment policy enforcement via a shared key cache, resulting in ciphertext that can be decrypted to multiple different plaintexts.\n\nTo remediate this issue, users should upgrade to version 3.3.1, 4.0.5 or above."
    },
    {
      "lang": "es",
      "value": "Degradación del algoritmo criptográfico en la capa de caché de Amazon AWS SDK de Cifrado para Python anterior a la versión 3.3.1 y anterior a la versión 4.0.5 podría permitir a un actor de amenaza local autenticado eludir la aplicación de la política de compromiso de clave a través de una caché de claves compartida, lo que resulta en texto cifrado que puede ser descifrado a múltiples textos planos diferentes.\n\nPara remediar este problema, los usuarios deberían actualizar a la versión 3.3.1, 4.0.5 o superior."
    }
  ],
  "affected": [
    {
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
      "affectedData": [
        {
          "vendor": "AWS",
          "product": "AWS Encryption SDK for Python",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "2",
              "lessThanOrEqual": "2.5.1",
              "versionType": "custom",
              "status": "affected"
            },
            {
              "version": "3",
              "lessThanOrEqual": "3.3.0",
              "versionType": "custom",
              "status": "affected"
            },
            {
              "version": "4",
              "lessThanOrEqual": "4.0.4",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/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",
          "baseScore": 5.7,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "HIGH",
          "attackRequirements": "PRESENT",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "vulnAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
          "baseScore": 4.7,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "HIGH",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-04-20T19:44:04.637540Z",
          "id": "CVE-2026-6550",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-757"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://aws.amazon.com/security/security-bulletins/2026-017-aws/",
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"
    },
    {
      "url": "https://github.com/aws/aws-encryption-sdk-python/releases/tag/v3.3.1",
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"
    },
    {
      "url": "https://github.com/aws/aws-encryption-sdk-python/releases/tag/v4.0.5",
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"
    },
    {
      "url": "https://github.com/aws/aws-encryption-sdk-python/security/advisories/GHSA-v638-38fc-rhfv",
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"
    }
  ]
}