CVE-2026-89049

Critical

Description

A server-side request forgery issue due to improper validation of equivalent address representations in the port forwarding to remote hosts functionality in Amazon AWS Systems Manager Agent (SSM Agent) before 3.3.4851.0 on all platforms might allow an authenticated remote user to bypass the remote destination denylist and reach link-local endpoints, potentially obtaining the temporary IAM role credentials of a managed instance and acting with that role's permissions from outside the instance, via a crafted destination host value that uses an alternate representation of a denied link-local address. To remediate this issue, users should upgrade to version 3.3.4851.0 or later.

SeverityCritical

CVSS9.9

Exploit probability—

ProductAmazon SSM Agent

PublishedSep 10, 2026

First seenSep 10, 2026

Weakness typeCWE-918Server-side request forgery (SSRF)CWE-1289CWE-1289

How to fix

Update

AWS Amazon SSM Agent3.3.4851.0 or later

Patches

github.com/aws/amazon-ssm-agent/releases/tag/3.3.4851.0

Vendor advisories

aws.amazon.com/security/security-bulletins/2026-107-aws/

Affected products

Product	Affected versions	Fixed in
AWS Amazon SSM Agent	v < 3.3.4851.0	3.3.4851.0

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