Medium 4.7Published Apr 20, 2026

CVE-2026-6550Cryptographic 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…

Updated under an hour ago (2026-10-19 11:10 UTC)

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Exploited in the last 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.

CVSS: 4.7 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
Weakness (CWE): CWE-757
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Awaiting Analysis
Record last updated: Jun 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

No affected products are listed yet.

References

https://aws.amazon.com/security/security-bulletins/2026-017-aws/
https://github.com/aws/aws-encryption-sdk-python/releases/tag/v3.3.1
https://github.com/aws/aws-encryption-sdk-python/releases/tag/v4.0.5
https://github.com/aws/aws-encryption-sdk-python/security/advisories/GHSA-v638-38fc-rhfv

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.