CVE-2026-6550

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

MEDIUM
4.7
CVSS Score
Published: April 20, 2026 at 07:20 PM UTC
Updated: October 26, 2026 at 10:10 PM UTC
1 product affected across 1 vendorEncryption SDK Python

Using AWS Encryption SDK for Python by AWS?

Get instant alerts when new vulnerabilities affect AWS Encryption SDK for Python - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM4.7
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2 ≤ v ≤ 2.5.13 ≤ v ≤ 3.3.04 ≤ v ≤ 4.0.4234

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.7MEDIUMAMZN
Attack Vector
LOCAL
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-757

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card