What’s Vulnerable › Vulnerabilities

CVE-2026-18654: Disabled SSH host key verification in Amazon AWS CLI EMR helper commands

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-03 · updated 2026-10-23
• Weakness: CWE-322

Description

Key exchange without entity authentication in the EMR SSH helper commands in Amazon AWS CLI before 1.45.28 and AWS CLI v2 before 2.35.3 might allow man-in-the-middle attackers to intercept SSHsessions and file transfers via network positioning between the client and the EMR cluster endpoint. To remediate this issue, users should upgrade to AWS CLI v1 1.45.28 or later, or AWS CLI v2 2.35.3 or later.

Affected products

• AWS CLI: before 1.45.28; from 2.0.0 before 2.35.3 — fixed in 1.45.28, 2.35.3

How to fix

Upgrade to a fixed version: AWS CLI 1.45.28, 2.35.3. Check the vendor advisory for mitigations.

References

• https://aws.amazon.com/security/security-bulletins/2026-071-aws/
• https://github.com/aws/aws-cli/blob/develop/CHANGELOG.rst
• https://github.com/aws/aws-cli/blob/v2/CHANGELOG.rst
• https://github.com/aws/aws-cli/security/advisories/GHSA-hqvf-45jj-mccq

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