CVE-2026-6550
Published:April 20, 2026
Updated:April 23, 2026
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.
Affected Packages
aws-encryption-sdk (PYTHON):
Affected version(s) >=4.0.0 <4.0.5Fix Suggestion:
Update to version 4.0.5aws-encryption-sdk (PYTHON):
Affected version(s) >=1.2.0 <3.3.1Fix Suggestion:
Update to version 3.3.1Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.7
Attack Vector
LOCAL
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.7
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')
EPSS
Base Score:
0.01
