CVE-2026-18654Medium· 6.8▾ SunlitAWS CLI: Disabled SSH host key verification in Amazon AWS CLI EMR helper commands
▾ Sunlit zone — Low / medium · no exploitation signal
impact 37.4 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Aug 6.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
0.3%
0.3% → 0.3%
Last analysed / modified upstream
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.
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
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 to incorporate the new fixes.
There is no workaround. The insecure SSH option was hardcoded and could not be overridden by the user.
If you have any questions or comments about this advisory, we ask that you contact AWS Security via our vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
We would like to thank Ali Sunbul for collaborating on this issue through the coordinated vulnerability disclosure process.
awscli < 1.45.28Upgrade to a patched release:
awscli 1.45.28Connected by shared product, vendor, weakness, or advisory.
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