AWS CLI: Disabled SSH host key verification in Amazon AWS CLI EMR helper commands

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N · score source

EPSS

• CVE-2026-18654: 0.46% estimated exploitation activity in the next 30 days; percentile 40.13 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The AWS Command Line Interface (AWS CLI) is a unified tool to manage AWS services from the command line. An issue exists where the EMR SSH helper commands (aws emr ssh, aws emr socks, aws emr put, aws emr get) passed StrictHostKeyChecking=no to the underlying SSH client, disabling host key verification. Impact A network-positioned actor could perform a man-in-the-middle action to intercept SSH sessions and file transfers between the client and EMR cluster instances. Successful exploitation requires the actor to have network access on the path between the client machine and the EMR cluster endpoint. This could result in full visibility of commands executed, files transferred, and credentials passed over the SSH session. Impacted versions: AWS CLI v1 <= 1.45.27, AWS CLI v2 <= 2.35.2 Patches This issue has been addressed in AWS CLI v1 version 1.45.28 and AWS CLI v2 version 2.35.3. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched…

Published by the source

6 Aug 2026, 20:15 UTC

Last modified by the source

6 Aug 2026, 20:15 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-hqvf-45jj-mccq

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# Patch Next advisory brief: CVE-2026-18654

Advisory: AWS CLI: Disabled SSH host key verification in Amazon AWS CLI EMR helper commands
IDs: CVE-2026-18654, GHSA-hqvf-45jj-mccq
Record: https://patchnext.com/advisories/cve-2026-18654 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: awscli 1.45.28. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI awscli: affected <= 1.45.27; fixed in 1.45.28

## Suggested inspection (read-only)
- `python -m pip show awscli`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on awscli.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-hqvf-45jj-mccq (GitHub-reviewed advisory GHSA-hqvf-45jj-mccq lists affected ranges: PyPI awscli >=0 <=1.45.27)

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