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 i

mediumCVSS 6.8CVE-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.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: medium — CVSS 6.8
Published: 2026-08-03
Last updated: 2026-08-04
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-18654

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-186540.29% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 21% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-18654	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownCVE-2026-18654 - Disabled SSH host key verification in AWS CLI EMR helper commandsaws

Recent advisories for Key exchange without

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

lowCVE-2026-59842: A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve255…nvd · 2026-07-21