CVE-2026-1777

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.

Impacted versions

• SageMaker Python SDK v3 < v3.2.0
• SageMaker Python SDK v2 < v2.256.0

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 [email protected]. Please do not create a public GitHub issue.

• 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.

CVE-2026-1777 has a CVSS score of 7.2 (High). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.2.0, 2.256.0); upgrading removes the vulnerable code path.

Kodem intelligence

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.

1. What is CVE-2026-1777? CVE-2026-1777 is a high-severity security vulnerability in sagemaker (pip), affecting versions >= 3.0, < 3.2.0. It is fixed in 3.2.0, 2.256.0.
2. How severe is CVE-2026-1777? CVE-2026-1777 has a CVSS score of 7.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of sagemaker are affected by CVE-2026-1777? sagemaker (pip) versions >= 3.0, < 3.2.0 is affected.
4. Is there a fix for CVE-2026-1777? Yes. CVE-2026-1777 is fixed in 3.2.0, 2.256.0. Upgrade to this version or later.
5. Is CVE-2026-1777 exploitable, and should I be worried? Whether CVE-2026-1777 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-1777 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-1777?
   • Upgrade sagemaker to 3.2.0 or later
   • Upgrade sagemaker to 2.256.0 or later