Vulnerability-Lookup

FKIE_CVE-2026-6550

Vulnerability from fkie_nvd - Published: 2026-04-20 20:16 - Updated: 2026-04-21 16:20

Severity ?

4.7 (Medium) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

Summary

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. To remediate this issue, users should upgrade to version 3.3.1, 4.0.5 or above.

References

	URL	Tags
	ff89ba41-3aa1-4d27-914a-91399e9639e5	https://aws.amazon.com/security/security-bulletins/2026-017-aws/
	ff89ba41-3aa1-4d27-914a-91399e9639e5	https://github.com/aws/aws-encryption-sdk-python/releases/tag/v3.3.1
	ff89ba41-3aa1-4d27-914a-91399e9639e5	https://github.com/aws/aws-encryption-sdk-python/releases/tag/v4.0.5
	ff89ba41-3aa1-4d27-914a-91399e9639e5	https://github.com/aws/aws-encryption-sdk-python/security/advisories/GHSA-v638-38fc-rhfv

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "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."
    }
  ],
  "id": "CVE-2026-6550",
  "lastModified": "2026-04-21T16:20:24.180",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 4.7,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 3.6,
        "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "HIGH",
          "attackRequirements": "PRESENT",
          "attackVector": "LOCAL",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 5.7,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "LOW",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "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",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-04-20T20:16:49.283",
  "references": [
    {
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
      "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"
    }
  ],
  "sourceIdentifier": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-757"
        }
      ],
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
      "type": "Secondary"
    }
  ]
}

CVE-2026-6550 (GCVE-0-2026-6550)

Vulnerability from cvelistv5 – Published: 2026-04-20 19:20 – Updated: 2026-04-20 19:44

Title

Key commitment policy bypass via shared key cache in AWS Encryption SDK for Python

Summary

Severity ?

4.7 (Medium)


                        
                          CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

5.7 (Medium)


                        
                          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

CWE

CWE-757 - Selection of Less-Secure algorithm during negotiation ('algorithm downgrade')

Assigner

AMZN

References

URL

Tags

	https://aws.amazon.com/security/security-bulletin…	vendor-advisory
	https://github.com/aws/aws-encryption-sdk-python/…	patch
	https://github.com/aws/aws-encryption-sdk-python/…	patch
	https://github.com/aws/aws-encryption-sdk-python/…	third-party-advisory

Impacted products

	Vendor	Product	Version
	AWS	AWS Encryption SDK for Python	Affected: 2 , ≤ 2.5.1 (custom) Affected: 3 , ≤ 3.3.0 (custom) Affected: 4 , ≤ 4.0.4 (custom)

Credits

1seal.org

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-6550",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-20T19:44:04.637540Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-20T19:44:11.685Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "AWS Encryption SDK for Python",
          "vendor": "AWS",
          "versions": [
            {
              "lessThanOrEqual": "2.5.1",
              "status": "affected",
              "version": "2",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "3.3.0",
              "status": "affected",
              "version": "3",
              "versionType": "custom"
            },
            {
              "lessThanOrEqual": "4.0.4",
              "status": "affected",
              "version": "4",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "1seal.org"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
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            }
          ],
          "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."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-620",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-620 Drop Encryption Level"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 4.7,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
            "version": "3.1"
          },
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          "scenarios": [
            {
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        },
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          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 5.7,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-757",
              "description": "CWE-757 Selection of Less-Secure algorithm during negotiation (\u0027algorithm downgrade\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-20T19:24:09.971Z",
        "orgId": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
        "shortName": "AMZN"
      },
      "references": [
        {
          "tags": [
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          "url": "https://aws.amazon.com/security/security-bulletins/2026-017-aws/"
        },
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          "tags": [
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          "url": "https://github.com/aws/aws-encryption-sdk-python/releases/tag/v4.0.5"
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          "url": "https://github.com/aws/aws-encryption-sdk-python/releases/tag/v3.3.1"
        },
        {
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            "third-party-advisory"
          ],
          "url": "https://github.com/aws/aws-encryption-sdk-python/security/advisories/GHSA-v638-38fc-rhfv"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Key commitment policy bypass via shared key cache in AWS Encryption SDK for Python",
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        "engine": "Vulnogram 1.0.1"
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    }
  },
  "cveMetadata": {
    "assignerOrgId": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
    "assignerShortName": "AMZN",
    "cveId": "CVE-2026-6550",
    "datePublished": "2026-04-20T19:20:23.383Z",
    "dateReserved": "2026-04-17T20:06:20.299Z",
    "dateUpdated": "2026-04-20T19:44:11.685Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

FKIE_CVE-2026-6550

CVE-2026-6550 (GCVE-0-2026-6550)

Tags

Sightings

Nomenclature