CVE-2026-18654

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.

Weakness

The product performs a key exchange with an actor without verifying the identity of that actor.

Potential 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