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🛡️ CVE-2026-8596 — sagemaker

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-312 NVD
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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

Summary

Amazon SageMaker Python SDK is an open-source library for training and deploying machine learning models on Amazon SageMaker. An issue exists where, under certain circumstances, the ModelBuilder/Serve component stores an HMAC signing key in cleartext as a container environment variable, which is returned in plaintext by SageMaker describe APIs.

Impact

When using ModelBuilder to build and deploy models with affected model servers (TorchServe, Multi-Model Server, TensorFlow Serving, SMD, or Triton), the SDK generates an HMAC secret key for model artifact integrity verification and stores it as the SAGEMAKER_SERVE_SECRET_KEY environment variable in the SageMaker model container configuration. This environment variable is returned in plaintext by the DescribeModel, DescribeEndpointConfig, and DescribeModelPackage APIs. A remote authenticated actor with permissions to call these describe APIs and S3 write access to the model artifact path could extract the key, forge valid integrity signatures for specially crafted model artifacts, and achieve code execution in inference containers with the SageMaker execution role's IAM permissions.

Impacted versions: >= v2.199.0 AND <= v2.257.1, >= v3.0.0 AND <= v3.7.1

Patches

This issue has been addressed in Amazon SageMaker Python SDK v2.257.2 and v3.8.0. AWS recommend upgrading to the latest version and rebuilding any models previously created with ModelBuilder using the updated SDK. Models created with affected versions may still have the HMAC key stored in their container environment variables until they are rebuilt with the patched SDK. Ensure any forked or derivative code is patched to incorporate the new fixes.

Workarounds

If upgrading is not immediately possible, users can manually remove the SAGEMAKER_SERVE_SECRET_KEY environment variable from existing SageMaker models by recreating the model without this variable in the container environment configuration.

References

If there any questions or comments about this advisory, contact AWS Security via the [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [[email protected]](mailto:[email protected]). Please do not create a public GitHub issue.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs administrative privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: High — administrative rights are needed first.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-8596 is classified as CWE-312: Cleartext Storage of Sensitive Information. Sensitive values are written to storage unencrypted and readable by anyone with access to it.

Affected software

CVE-2026-8596 is recorded against 2 packages.

  • sagemaker (from 3.0.0 up to 3.8.0)
  • unknown

Timeline and source

Published on 21 May 2026 and last revised on 13 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
nvd.nist.gov (Advisory)
aws.amazon.com (Web)
github.com (Package)
github.com (Web)
github.com (Web)

Other advisories for this package

sagemaker has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-312: Cleartext Storage of Sensitive Information) in other software:

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CWE CWE-312
Public Exploit ✅ No
Source NVD
Published 2026-05-21
Updated 2026-08-20
Modified 2026-07-13
Fix URL N/A

Affected Packages

Software From version Fixed in
sagemaker 3.0.0 3.8.0
unknown — —

Similar Threats

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