Is CVE-2026-18654 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-18654 being exploited in the wild.

How severe is CVE-2026-18654?

High severity, with a CVSS score of 6.8, published 3 August 2026.

Which products and versions are affected?

AWS CLI v1 <= 1.45.27; AWS CLI v2 <= 2.35.2; awscli (PyPI) <= 1.45.27, ECOSYSTEM:introduced=0,fixed=1.45.28.

Is there a fix for CVE-2026-18654?

Yes. awscli (PyPI): upgrade to 1.45.28 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-18654 attacked?

It is attacked over the network or from the adjacent network, in a web application.

Am I affected by CVE-2026-18654?

Check whether you run Amazon AWS, AWS CLI v1, AWS CLI v2 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

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

Q: Which products and versions are affected?

AWS CLI v1 <= 1.45.27; AWS CLI v2 <= 2.35.2; awscli (PyPI) <= 1.45.27, ECOSYSTEM:introduced=0,fixed=1.45.28.

Q: Is there a fix for CVE-2026-18654?

Yes. awscli (PyPI): upgrade to 1.45.28 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-18654 attacked?

It is attacked over the network or from the adjacent network, in a web application.

Q: Am I affected by CVE-2026-18654?

Check whether you run Amazon AWS, AWS CLI v1, AWS CLI v2 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-18654 · Severity: high · CVSS 6.8 · Published 2026-08-03

AWS CLI includes helper commands for managing Elastic MapReduce (EMR) clusters that disable SSH host key verification, a critical security check that validates a server's identity. An attacker on the network can intercept and manipulate SSH connections to EMR cluster nodes, potentially stealing credentials, injecting malicious commands, or redirecting traffic to attacker-controlled systems. Organizations using AWS CLI to provision or manage EMR clusters are at risk of unauthorized cluster access and data exposure.

Technologies: Amazon AWS, awscli (PyPI). Vendors: Amazon, AWS, PyPI.

Quick answers

Is CVE-2026-18654 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-18654 being exploited in the wild.
How severe is CVE-2026-18654?: High severity, with a CVSS score of 6.8, published 3 August 2026.
Which products and versions are affected?: AWS CLI v1 <= 1.45.27; AWS CLI v2 <= 2.35.2; awscli (PyPI) <= 1.45.27, ECOSYSTEM:introduced=0,fixed=1.45.28.
Is there a fix for CVE-2026-18654?: Yes. awscli (PyPI): upgrade to 1.45.28 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-18654 attacked?: It is attacked over the network or from the adjacent network, in a web application.
Am I affected by CVE-2026-18654?: Check whether you run Amazon AWS, AWS CLI v1, AWS CLI v2 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

awscli (PyPI): upgrade to 1.45.28 or later
```
pip install "awscli>=1.45.28"
```

Technical details

The AWS CLI EMR helper commands disable SSH host key verification by not properly validating server public keys during SSH connection establishment. This allows man-in-the-middle (MITM) attacks on the SSH channel used to configure and manage EMR cluster nodes. The vulnerability affects network-based attackers in a position to intercept or redirect SSH traffic (adjacent network, compromised gateway, or rogue access point). An attacker can intercept credentials passed during cluster provisioning, execute arbitrary commands on cluster nodes, or perform privilege escalation. No authentication bypass is required; the flaw exists in the SSH client configuration itself. AWS has released patches; users should update to the latest AWS CLI version.

Affected products

Amazon AWS CLI versions with EMR helper commands

Identifiers

CVE-2026-18654
GHSA-hqvf-45jj-mccq
PYSEC-2026-3627

Timeline

2026-09-09: disclosed

References

https://aws.amazon.com/security/security-bulletins/rss/2026-071-aws/

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