CVE-2026-6550 MEDIUM

CVE-2026-6550: Key commitment policy bypass via shared key cache in AWS Encryption SDK for Python

Vendor Aws
Product AWS Encryption SDK for Python
Weakness CWE-757
Published April 20, 2026
Last update April 20, 2026

CVSS base score

4.7/10
Attack vector Local
Attack complexity High
Privileges required Low
User interaction None
Confidentiality None
Integrity High

CVSS vector

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

What the vulnerability does

Description

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.

Key dates

Disclosure timeline

April 20, 2026 CVE published
April 20, 2026 Record updated