Server-side request forgery in the Session Manager port forwarding functionality in AWS...

UnratedCVE-2026-89049 · Published Sep 10, 2026

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: < 3.3.4851.0 (all versions supporting remote-host port forwarding) Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.