CVE-2026-6550

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.

CVSS v3 4.7 MEDIUM

4.7^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.0 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://aws.amazon.com/security/security-bulletins/2026-017-aws/
https://github.com/aws/aws-encryption-sdk-python/releases/tag/v3.3.1
https://github.com/aws/aws-encryption-sdk-python/releases/tag/v4.0.5
https://github.com/aws/aws-encryption-sdk-python/security/advisories/GHSA-v638-38fc-rhfv

Configurations

No configuration.

History

20 Apr 2026, 20:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-04-20 20:16

Updated : 2026-04-21 16:20

NVD link : CVE-2026-6550

Mitre link : CVE-2026-6550

CVE.ORG link : CVE-2026-6550

JSON object : View

Products Affected

No product.

CWE

CWE-757

Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')

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