CVE-2026-8596 Cleartext storage of HMAC signing key in Amazon SageMaker Python SDK ModelBuilder/Serve path
Authenticated attackers can extract HMAC keys from API responses to forge signatures and execute code in inference containers.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-8596?
CVE-2026-8596 is a high-severity vulnerability in AWS Amazon SageMaker Python SDK, published on 14 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
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.
Weakness: CWE-312
Which versions are affected by CVE-2026-8596?
5 open source packages ship an affected version, including sagemaker.
| Package | Affected | Fixed in |
|---|---|---|
sagemaker PyPI | From 2.199.0 | 2.257.2, 3.8.0 |
sagemaker PyPI | From 2.199.0 | 2.257.2 |
sagemaker PyPI | From 2.199.0 | 2.257.2 |
sagemaker PyPI | From 3.0.0 | 3.8.0 |
sagemaker PyPI | From 3.0.0 | 3.8.0 |
How do I fix CVE-2026-8596?
Upgrade sagemaker to a fixed version for your release line: 2.257.2 or 3.8.0.
Is CVE-2026-8596 being exploited?
There is no known exploitation of CVE-2026-8596 in the wild and no public exploit code.
Sources
Also known as GHSA-7hh5-prp2-mfh5, PYSEC-2026-3059.