Bulletin ID: 2026-148-AWS
Scope: AWS
Content Type: Important (requires attention)
Publication Date: 10/23/2026 10:30 AM PDT

Description:

Amazon Web Services Multi Model Server (MMS) is an open source tool for serving machine learning models for inference. It was published by AWS on GitHub, PyPI, and Docker Hub, and reached end of life; its source repository has been archived and read-only since November 20, 2025.

We identified the following issues in MMS:

• CVE-2026-115812: An issue in model archive extraction could allow a crafted model archive to write files outside the intended directory, potentially resulting in code execution with the privileges of the MMS process.
• CVE-2026-115813: An issue in the model download path could allow the MMS management interface to be directed to make requests to unintended network destinations.

In both cases, the MMS management interface does not require authentication. Deployments that bind this interface to a network-accessible address are at increased risk.

Because MMS has reached end of life and is no longer maintained, we recommend that users migrate to a supported model-serving solution.

Impacted versions: <=1.1.11 (all released versions)

Resolution:

Multi Model Server is end of life and no fixed version is available or planned on any distribution channel. We recommend that customers discontinue use of Multi Model Server and migrate to a supported model serving solution. Customers who maintain forked or derivative code should apply equivalent changes themselves: reject any archive entry whose resolved path falls outside the extraction directory, and restrict the model-download path to an explicit allowlist of permitted URLs.

Workarounds:

Where a deployment binds the inference and management interfaces to separate ports, bind the management interface to the loopback address so it is not reachable from untrusted networks, and do not pass externally supplied URLs to the model-download path. This workaround is not available in every configuration. The configuration shipped for SageMaker-style deployments binds the management interface to all addresses on the same port as inference, so management cannot be moved to loopback there without also disabling model loading. Deployments in that configuration should prioritize migration, and in the interim should ensure the serving port is reachable only by trusted callers.

References:

• CVE-2026-115812
• CVE-2026-115813

Acknowledgement:

We would like to thank Sujal Tuladhar for collaborating on this issue through the coordinated vulnerability disclosure process.

Please email aws-security@amazon.com with any security questions or concerns.