CVE-2026-6550: Aws Encryption SDK For Python

Medium severity, CVSS 4.7. EPSS: 0.1% chance of exploitation in the next 30 days.

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 products

• Aws Aws Encryption SDK For Python: from 2, up to and including 2.5.1; from 3, up to and including 3.3.0; from 4, up to and including 4.0.4

Published 2026-04-20. Last modified 2026-06-17.