CVE-2026-83551

Cleartext HMAC key stored in SageMaker pipeline decorators enables forged signatures and code execution.

• CVSS 8.5
• 312
• Cryptographic
• Remote

Cleartext storage of sensitive information in the @step and @remote decorator pipeline component in Amazon SageMaker Python SDK before v3.11.0 and v2.256.0 might allow an authenticated remote user to extract the HMAC signing key from SageMaker DescribePipeline API responses and forge valid integrity signatures for specially crafted function payloads, achieving code execution in another user's pipeline execution context within the same AWS account.

CVE

CVE-2026-83551

CWE

312

CVSS base score

8.5

Published

2026-09-01

OWASP

A02 Cryptographic Failures

Orthogonal defect classification

Assignment

Code defect classification

Incorrect Assignment

Category

Cryptographic

Subcategory

Cryptographic Implementation Error

Accessibility scope

Remote

Impact

Arbitrary Code Execution

Affected component

Amazon SageMaker Python SDK

Fixed by upgrading

Yes

Solution

Upgrade the Amazon SageMaker Python SDK to v3.11.0 or newer (or v2.256.0 or newer).

import json
from sagemaker.workflow.pipeline import Pipeline
from sagemaker.workflow.steps import step, remote

@step
def my_step(input_uri: str):
    # VULNERABLE: stores HMAC signing key in cleartext step metadata
    signing_key = "hmac-secret-key-0123"
    payload = {"input_uri": input_uri, "signing_key": signing_key}
    return json.dumps(payload)

pipeline = Pipeline(
    name="example-pipeline",
    steps=[my_step],
    description="Demo pipeline with vulnerable step"
)

import json
from sagemaker.workflow.pipeline import Pipeline
from sagemaker.workflow.steps import step, remote
from sagemaker.secrets_manager import SecretsManager

secrets = SecretsManager()

@step
def my_step(input_uri: str):
    # FIX: retrieve HMAC key from Secrets Manager instead of embedding it
    signing_key = secrets.get_secret_value(SecretId="my-hmac-key")["SecretString"]
    payload = {"input_uri": input_uri, "signing_key": signing_key}
    return json.dumps(payload)

pipeline = Pipeline(
    name="example-pipeline",
    steps=[my_step],
    description="Demo pipeline with patched step"
)

__VAITP_MODEL_REFUSED__

@misc{vaitp:cve202683551,
  title        = {{Cleartext HMAC key stored in SageMaker pipeline decorators enables forged signatures and code execution.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2026},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2026-83551},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2026-83551/}}
}