CVE-2026-8596

Cleartext storage of HMAC signing key in Amazon SageMaker Python SDK ModelBuilder/Serve path

Assigner: AMZN
Reserved: 14.05.2026 Published: 14.05.2026 Updated: 14.05.2026

Cleartext storage of sensitive information in the ModelBuilder/Serve component in Amazon SageMaker Python SDK before v2.257.2 and v3 before v3.8.0 might allow a remote authenticated actor to extract the HMAC signing key from SageMaker API responses and forge valid integrity signatures for specially crafted model artifacts, achieving code execution in inference containers. This issue requires a remote authenticated actor with permissions to call SageMaker describe APIs and S3 write access to the model artifact path.

To remediate this issue, we recommend upgrading to Amazon SageMaker Python SDK v2.257.2 or v3.8.0 and rebuild any models previously created with ModelBuilder using the updated SDK.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 7.2

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	High	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H
CVSS Score: 8.5

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	High
Attack Complexity	Low	Integrity	None	Integrity	High
Attack Requirements	None	Availability	None	Availability	High
Privileges Required	High
User Interaction	None

CVSS 4.0

Product Status

Vendor	Amazon SageMaker Python SDK
Product	AWS
Versions	Default: unaffected affected from 2.199.0 to 2.257.1 (incl.) affected from 3.0.0 to 3.7.1 (incl.)

Vendor

Amazon SageMaker Python SDK

Product

AWS

Versions

Default: unaffected

affected from 2.199.0 to 2.257.1 (incl.)
affected from 3.0.0 to 3.7.1 (incl.)

References

Problem Types

CWE-312 Cleartext storage of sensitive information CWE

Impacts