CVE-2026-89049 - Server-side request forgery in the Session Manager port forwarding functionality in AWS Systems Manager Agent

Bulletin ID: 2026-107-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 09/10/2026 11:30 AM PDT Description: AWS Systems Manager Agent (SSM Agent) is software that runs on managed nodes (EC2 instances, on-premises servers, and other supported machines) and processes requests from the AWS Systems Manager service, enabling capabilities including Session Manager port forwarding to remote hosts. We identified CVE-2026-89049, a server-side request forgery issue in the remote-host port forwarding functionality. Due to improper validation of equivalent address representations, an authenticated user with port-forwarding permission could bypass the remote destination denylist and reach link-local endpoints, potentially obtaining the managed instance's temporary IAM role credentials and acting with that role's permissions from outside the instance. Impacted versions:
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