CVE-2026-6550

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data tampering.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-04-20 20:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 22:10 UTC Last updatedMost recent change to the record

Details

Published

2026-04-20 20:16 UTC

Last modified

2026-10-26 22:10 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-757

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 5.7

Attack vector

Local

Complexity

High

Attack requirements

Present

Privileges needed

Low

User interaction

None

Confidentiality

None

Integrity

High

Availability

None