CVE-2026-1777: SageMaker Python SDK Exposed HMAC Vulnerability
Summary
CVE-2026-1777: SageMaker Python SDK has Exposed HMAC. Affects sagemaker across 2 version ranges.
< 2.256.0
>= 3.0, < 3.2.0
Fixed in 2.256.0 or 3.2.0, depending on the release line you run. How to fix ↓
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Background
The SageMaker Python SDK is an open-source library designed for training and deploying machine learning models on Amazon SageMaker. It provides a user-friendly interface for developers to interact with SageMaker services, enabling seamless integration of machine learning workflows. However, a critical vulnerability has been identified that compromises the security of HMAC secret keys used within the SDK.
Vulnerability Detail
The vulnerability arises from the improper handling of HMAC secret keys, which are stored in environment variables and can be disclosed via the DescribeTrainingJob API. This exposure allows attackers with the appropriate permissions to extract HMAC keys, leading to potential function and payload tampering, arbitrary code execution in the training environment, and risks to sensitive data and credentials. The implications extend to cross-tenant risks in shared environments, where a compromised HMAC key could be used to perform unauthorized actions against other users' workloads.
How To Fix
Latest published version: 3.27.0 as of 22 Oct 2026
pip install --upgrade "sagemaker==3.27.0"Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 2.256.02.256.0pip install --upgrade "sagemaker==2.256.0" -
>= 3.0, < 3.2.03.2.0pip install --upgrade "sagemaker==3.2.0"
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Workaround
As a temporary workaround, customers using self-signed certificates for internal model downloads should add their private Certificate Authority (CA) certificate to the container image instead of relying on the SDK's previous insecure configuration. This approach enhances security while accommodating internal trusted domains.
Conclusion
The SageMaker Python SDK vulnerability (CVE-2026-1777) poses significant risks due to the exposure of HMAC secret keys. Users are strongly advised to upgrade to the latest patched versions and implement the recommended workarounds to mitigate potential threats.
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FAQ
The vulnerability involves the exposure of HMAC secret keys, which can be accessed through the DescribeTrainingJob API, leading to potential unauthorized actions and code execution.
Users of the SageMaker Python SDK versions prior to v2.256.0 and v3.2.0 are affected by this vulnerability.
Consequences include function and payload tampering, arbitrary code execution, and risks to sensitive data and credentials, especially in shared environments.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The CVSS score of this vulnerability is 7.2, indicating a high severity level.
References
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