CVE-2026-83551Network attack vector

Cross-user code execution via exposed HMAC key

Published Sep 1, 2026 · Updated Sep 1, 2026

Cleartext key storage in Amazon SageMaker Python SDK v3 before 3.11.0 and v2 before 2.256.0 allows remote authenticated users to execute code. The @step and @remote pipeline path places its symmetric HMAC key in pipeline definitions returned by DescribePipeline, enabling forged signatures for attacker-controlled serialized payloads in S3. Exploitation requires same-account DescribePipeline and target-bucket PutObject permissions; a victim pipeline then deserializes the payload under the victim execution role.

CVSS severity7.2
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cleartext key storage in Amazon SageMaker Python SDK v3 before 3.11.0 and v2 before 2.256.0 allows remote authenticated users to execute code. The @step and @remote pipeline path places its symmetric HMAC key in pipeline definitions returned by DescribePipeline, enabling forged signatures for attacker-controlled serialized payloads in S3. Exploitation requires same-account DescribePipeline and target-bucket PutObject permissions; a victim pipeline then deserializes the payload under the victim execution role.

The record

CVE
CVE-2026-83551
Published
Sep 1, 2026
Updated
Sep 1, 2026
Vendor
Amazon Web Services
Product
Amazon SageMaker Python SDK
Classifications
CWE-312, CAPEC-586, T1059.009
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.256.0
  2. Affected versionversion=0 <3.11.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Amazon Web Services · Amazon SageMaker Python SDKversion=0 <2.256.0; version=0 <3.11.0

Published CVSS scores

7.2Amazon Web ServicesCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
8.5Amazon Web ServicesCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-312Cleartext Storage of Sensitive Information
CAPEC-586Object Injection
T1059.009Command and Scripting Interpreter: Cloud API

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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