CVE-2026-18654 Disabled SSH host key verification in Amazon AWS CLI EMR helper commands
Man-in-the-middle attackers can intercept SSH sessions and file transfers in AWS CLI EMR commands due to disabled host key verification.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-18654?
CVE-2026-18654 is a medium-severity vulnerability in aws-cli, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-322
Which versions are affected by CVE-2026-18654?
3 open source packages ship an affected version, including awscli. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
awscli PyPI | All versions | 1.45.28 |
awscli PyPI | All versions | 1.45.28 |
awscli PyPI | All versions | 1.45.28 |
Products include Amazon Aws Command Line Interface.
How do I fix CVE-2026-18654?
Upgrade awscli to 1.45.28 or later.
Is CVE-2026-18654 being exploited?
There is no known exploitation of CVE-2026-18654 in the wild and no public exploit code.
Other vulnerabilities in aws-cli
Sources
Also known as GHSA-hqvf-45jj-mccq, MINI-3xhr-75w2-p922, MINI-7pcv-frfh-2cjv, PYSEC-2026-3627.