SageMaker Python SDK has Exposed HMAC
Summary
SageMaker Python SDK is an open source library for training and deploying machine learning models on Amazon SageMaker. An issue where the HMAC secret key is stored in environment variables and disclosed via the DescribeTrainingJob API has been identified.
Impact
- Function and Payload Tampering: Attackers with DescribeTrainingJob permissions may extract HMAC secret keys and forge serialized function payloads stored in S3. These tampered payloads would be processed and executed without triggering integrity validation errors, enabling unintended code substitution.
- Arbitrary Code Execution in the Training Environment: An third party with both DescribeTrainingJob permissions and write access to the job's S3 output location can extract the HMAC key, craft inappropriate Python objects, and achieve remote code execution in the client's Python process when the victim retrieves remote function results.
- Data and Credentials Handling: Arbitrary remote code execution may interact with sensitive data, model artifacts, environment variables, and potentially AWS metadata.
- Cross-Tenant or Shared Environment Risks: In multi-tenant, shared S3 bucket, a disclosed HMAC key could act as a pivot point to perform inappropriate actions against other users' remote function workloads. This could leverage the IAM permissions, shared S3 buckets, or VPC resources to compromise adjacent services or data.
Impacted versions
- SageMaker Python SDK v3 < v3.2.0
- SageMaker Python SDK v2 < v2.256.0
Patches
This issue has been addressed in SageMaker Python SDK version v3.2.0 and v2.256.0. Upgrading to the latest version immediately and ensuring any forked or derivative code is patched to incorporate the new fixes is recommended.
Workarounds
Customers using self-signed certificates for internal model downloads should add their private Certificate Authority (CA) certificate to the container image rather than relying on the SDK’s previous insecure configuration. This opt-in approach maintains security while accommodating internal trusted domains.
Resources
If there are any questions or comments about this advisory, contact AWS Security via the vulnerability reporting page or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | sagemaker | >= 3.0, < 3.2.0, < 2.256.0 | 3.2.0, 2.256.0 |
References
- https://github.com/aws/sagemaker-python-sdk/security/advisories/GHSA-rjrp-m2jw-pv9c
- https://nvd.nist.gov/vuln/detail/CVE-2026-1777
- https://github.com/aws/sagemaker-python-sdk/commit/708c7b2f4135ecaec55973d098f3dbe98b657933
- https://github.com/aws/sagemaker-python-sdk/commit/fb0d789db4fd5fecde5509963939369f4c7ce63b
- https://aws.amazon.com/security/security-bulletins/2026-004-AWS
- https://github.com/aws/sagemaker-python-sdk
- https://github.com/aws/sagemaker-python-sdk/releases/tag/v2.256.0
- https://github.com/aws/sagemaker-python-sdk/releases/tag/v3.2.0
- https://pypi.org/project/sagemaker
- https://github.com/advisories/GHSA-rjrp-m2jw-pv9c
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-201, CWE-295, CWE-319- Platform
- Python (PyPI)
- Package
sagemaker- Disclosed
- 02.02.2026
- Updated
- 11.10.2026 13:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-1888 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-rjrp-m2jw-pv9c - CC BY 4.0
Vulnerability history: sagemaker
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 8
- First → latest
- 05.2024 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 6
- Medium 2
Disclosures per year
- 2024: 2
- 2025: 1
- 2026: 5
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