CVE-2026-18654Network attack vector

Session interception via disabled SSH host verification

Published Aug 3, 2026 · Updated Aug 3, 2026

Unauthenticated key exchange in AWS CLI v1 before 1.45.28 and v2 before 2.35.3 allows man-in-the-middle attackers to intercept EMR SSH traffic. The EMR ssh, socks, put, and get helpers hardcode StrictHostKeyChecking=no when invoking the underlying SSH client, preventing server host-key validation. Exploitation requires network positioning between the client and EMR endpoint and exposes session commands, transferred files, and credentials to interception.

CVSS severity6.9
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unauthenticated key exchange in AWS CLI v1 before 1.45.28 and v2 before 2.35.3 allows man-in-the-middle attackers to intercept EMR SSH traffic. The EMR ssh, socks, put, and get helpers hardcode StrictHostKeyChecking=no when invoking the underlying SSH client, preventing server host-key validation. Exploitation requires network positioning between the client and EMR endpoint and exposes session commands, transferred files, and credentials to interception.

The record

CVE
CVE-2026-18654
Published
Aug 3, 2026
Updated
Aug 3, 2026
Vendor
Amazon Web Services
Product
AWS Command Line Interface
Classifications
CWE-322, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 <=1.45.27
  2. Affected versionversion=0 <=2.35.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Amazon Web Services · AWS Command Line Interfaceversion=0 <=1.45.27; version=0 <=2.35.2

Published CVSS scores

6.9Amazon Web ServicesCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N
6.8Amazon Web ServicesCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-322Key Exchange without Entity Authentication
T1557Adversary-in-the-Middle

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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