CVE-2026-1777Network attack vector

Authenticated code execution via exposed HMAC signing key

Published Feb 2, 2026 · Updated Feb 2, 2026

HMAC exposure in Amazon SageMaker Python SDK version 2 before 2.256.0 or version 3 before 3.2.0 allows remote authenticated users to obtain the key. DescribeTrainingJob returns the ModelBuilder per-job signing secret from an environment variable, enabling forged cloud-pickled S3 payloads to pass integrity checks. The attacker needs DescribeTrainingJob permission and write access to the training job output location; execution occurs when the client retrieves remote-function results.

CVSS severity8.5
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HMAC exposure in Amazon SageMaker Python SDK version 2 before 2.256.0 or version 3 before 3.2.0 allows remote authenticated users to obtain the key. DescribeTrainingJob returns the ModelBuilder per-job signing secret from an environment variable, enabling forged cloud-pickled S3 payloads to pass integrity checks. The attacker needs DescribeTrainingJob permission and write access to the training job output location; execution occurs when the client retrieves remote-function results.

The record

CVE
CVE-2026-1777
Published
Feb 2, 2026
Updated
Feb 2, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-319, CAPEC-117, T1552, T1059.006
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 2, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.5AMZNCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H
7.2AMZNCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-319Cleartext Transmission of Sensitive Information
CAPEC-117Interception
T1552Unsecured Credentials
T1059.006Python

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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