CVE-2026-18654 (CVSS 6.8)

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.

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CVSS v3.1 Score

6.8

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0029

Probability of exploitation

0.21%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-322 CWE-322

References

Other 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

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2026-18654? +

CVE-2026-18654 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0029, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-18654? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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